Improve ALTER DOMAIN / DROP CONSTRAINT with nonexistent constraint

[postgresql] / src / include / nodes / parsenodes.h

/*-------------------------------------------------------------------------
 *
 * parsenodes.h
 *        definitions for parse tree nodes
 *
 * Many of the node types used in parsetrees include a "location" field.
 * This is a byte (not character) offset in the original source text, to be
 * used for positioning an error cursor when there is an error related to
 * the node.  Access to the original source text is needed to make use of
 * the location.
 *
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/nodes/parsenodes.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PARSENODES_H
#define PARSENODES_H

#include "nodes/bitmapset.h"
#include "nodes/primnodes.h"
#include "nodes/value.h"

/* Possible sources of a Query */
typedef enum QuerySource
{
        QSRC_ORIGINAL,                          /* original parsetree (explicit query) */
        QSRC_PARSER,                            /* added by parse analysis (now unused) */
        QSRC_INSTEAD_RULE,                      /* added by unconditional INSTEAD rule */
        QSRC_QUAL_INSTEAD_RULE,         /* added by conditional INSTEAD rule */
        QSRC_NON_INSTEAD_RULE           /* added by non-INSTEAD rule */
} QuerySource;

/* Sort ordering options for ORDER BY and CREATE INDEX */
typedef enum SortByDir
{
        SORTBY_DEFAULT,
        SORTBY_ASC,
        SORTBY_DESC,
        SORTBY_USING                            /* not allowed in CREATE INDEX ... */
} SortByDir;

typedef enum SortByNulls
{
        SORTBY_NULLS_DEFAULT,
        SORTBY_NULLS_FIRST,
        SORTBY_NULLS_LAST
} SortByNulls;

/*
 * Grantable rights are encoded so that we can OR them together in a bitmask.
 * The present representation of AclItem limits us to 16 distinct rights,
 * even though AclMode is defined as uint32.  See utils/acl.h.
 *
 * Caution: changing these codes breaks stored ACLs, hence forces initdb.
 */
typedef uint32 AclMode;                 /* a bitmask of privilege bits */

#define ACL_INSERT              (1<<0)  /* for relations */
#define ACL_SELECT              (1<<1)
#define ACL_UPDATE              (1<<2)
#define ACL_DELETE              (1<<3)
#define ACL_TRUNCATE    (1<<4)
#define ACL_REFERENCES  (1<<5)
#define ACL_TRIGGER             (1<<6)
#define ACL_EXECUTE             (1<<7)  /* for functions */
#define ACL_USAGE               (1<<8)  /* for languages, namespaces, FDWs, and
                                                                 * servers */
#define ACL_CREATE              (1<<9)  /* for namespaces and databases */
#define ACL_CREATE_TEMP (1<<10) /* for databases */
#define ACL_CONNECT             (1<<11) /* for databases */
#define N_ACL_RIGHTS    12              /* 1 plus the last 1<<x */
#define ACL_NO_RIGHTS   0
/* Currently, SELECT ... FOR UPDATE/FOR SHARE requires UPDATE privileges */
#define ACL_SELECT_FOR_UPDATE   ACL_UPDATE


/*****************************************************************************
 *      Query Tree
 *****************************************************************************/

/*
 * Query -
 *        Parse analysis turns all statements into a Query tree (via transformStmt)
 *        for further processing by the rewriter and planner.
 *
 *        Utility statements (i.e. non-optimizable statements) have the
 *        utilityStmt field set, and the Query itself is mostly dummy.
 *        DECLARE CURSOR is a special case: it is represented like a SELECT,
 *        but the original DeclareCursorStmt is stored in utilityStmt.
 *
 *        Planning converts a Query tree into a Plan tree headed by a PlannedStmt
 *        node --- the Query structure is not used by the executor.
 */
typedef struct Query
{
        NodeTag         type;

        CmdType         commandType;    /* select|insert|update|delete|utility */

        QuerySource querySource;        /* where did I come from? */

        bool            canSetTag;              /* do I set the command result tag? */

        Node       *utilityStmt;        /* non-null if this is DECLARE CURSOR or a
                                                                 * non-optimizable statement */

        int                     resultRelation; /* rtable index of target relation for
                                                                 * INSERT/UPDATE/DELETE; 0 for SELECT */

        IntoClause *intoClause;         /* target for SELECT INTO / CREATE TABLE AS */

        bool            hasAggs;                /* has aggregates in tlist or havingQual */
        bool            hasWindowFuncs; /* has window functions in tlist */
        bool            hasSubLinks;    /* has subquery SubLink */
        bool            hasDistinctOn;  /* distinctClause is from DISTINCT ON */
        bool            hasRecursive;   /* WITH RECURSIVE was specified */
        bool            hasModifyingCTE;        /* has INSERT/UPDATE/DELETE in WITH */
        bool            hasForUpdate;   /* FOR UPDATE or FOR SHARE was specified */

        List       *cteList;            /* WITH list (of CommonTableExpr's) */

        List       *rtable;                     /* list of range table entries */
        FromExpr   *jointree;           /* table join tree (FROM and WHERE clauses) */

        List       *targetList;         /* target list (of TargetEntry) */

        List       *returningList;      /* return-values list (of TargetEntry) */

        List       *groupClause;        /* a list of SortGroupClause's */

        Node       *havingQual;         /* qualifications applied to groups */

        List       *windowClause;       /* a list of WindowClause's */

        List       *distinctClause; /* a list of SortGroupClause's */

        List       *sortClause;         /* a list of SortGroupClause's */

        Node       *limitOffset;        /* # of result tuples to skip (int8 expr) */
        Node       *limitCount;         /* # of result tuples to return (int8 expr) */

        List       *rowMarks;           /* a list of RowMarkClause's */

        Node       *setOperations;      /* set-operation tree if this is top level of
                                                                 * a UNION/INTERSECT/EXCEPT query */

        List       *constraintDeps; /* a list of pg_constraint OIDs that the query
                                                                 * depends on to be semantically valid */
} Query;


/****************************************************************************
 *      Supporting data structures for Parse Trees
 *
 *      Most of these node types appear in raw parsetrees output by the grammar,
 *      and get transformed to something else by the analyzer.  A few of them
 *      are used as-is in transformed querytrees.
 ****************************************************************************/

/*
 * TypeName - specifies a type in definitions
 *
 * For TypeName structures generated internally, it is often easier to
 * specify the type by OID than by name.  If "names" is NIL then the
 * actual type OID is given by typeOid, otherwise typeOid is unused.
 * Similarly, if "typmods" is NIL then the actual typmod is expected to
 * be prespecified in typemod, otherwise typemod is unused.
 *
 * If pct_type is TRUE, then names is actually a field name and we look up
 * the type of that field.      Otherwise (the normal case), names is a type
 * name possibly qualified with schema and database name.
 */
typedef struct TypeName
{
        NodeTag         type;
        List       *names;                      /* qualified name (list of Value strings) */
        Oid                     typeOid;                /* type identified by OID */
        bool            setof;                  /* is a set? */
        bool            pct_type;               /* %TYPE specified? */
        List       *typmods;            /* type modifier expression(s) */
        int32           typemod;                /* prespecified type modifier */
        List       *arrayBounds;        /* array bounds */
        int                     location;               /* token location, or -1 if unknown */
} TypeName;

/*
 * ColumnRef - specifies a reference to a column, or possibly a whole tuple
 *
 * The "fields" list must be nonempty.  It can contain string Value nodes
 * (representing names) and A_Star nodes (representing occurrence of a '*').
 * Currently, A_Star must appear only as the last list element --- the grammar
 * is responsible for enforcing this!
 *
 * Note: any array subscripting or selection of fields from composite columns
 * is represented by an A_Indirection node above the ColumnRef.  However,
 * for simplicity in the normal case, initial field selection from a table
 * name is represented within ColumnRef and not by adding A_Indirection.
 */
typedef struct ColumnRef
{
        NodeTag         type;
        List       *fields;                     /* field names (Value strings) or A_Star */
        int                     location;               /* token location, or -1 if unknown */
} ColumnRef;

/*
 * ParamRef - specifies a $n parameter reference
 */
typedef struct ParamRef
{
        NodeTag         type;
        int                     number;                 /* the number of the parameter */
        int                     location;               /* token location, or -1 if unknown */
} ParamRef;

/*
 * A_Expr - infix, prefix, and postfix expressions
 */
typedef enum A_Expr_Kind
{
        AEXPR_OP,                                       /* normal operator */
        AEXPR_AND,                                      /* booleans - name field is unused */
        AEXPR_OR,
        AEXPR_NOT,
        AEXPR_OP_ANY,                           /* scalar op ANY (array) */
        AEXPR_OP_ALL,                           /* scalar op ALL (array) */
        AEXPR_DISTINCT,                         /* IS DISTINCT FROM - name must be "=" */
        AEXPR_NULLIF,                           /* NULLIF - name must be "=" */
        AEXPR_OF,                                       /* IS [NOT] OF - name must be "=" or "<>" */
        AEXPR_IN                                        /* [NOT] IN - name must be "=" or "<>" */
} A_Expr_Kind;

typedef struct A_Expr
{
        NodeTag         type;
        A_Expr_Kind kind;                       /* see above */
        List       *name;                       /* possibly-qualified name of operator */
        Node       *lexpr;                      /* left argument, or NULL if none */
        Node       *rexpr;                      /* right argument, or NULL if none */
        int                     location;               /* token location, or -1 if unknown */
} A_Expr;

/*
 * A_Const - a literal constant
 */
typedef struct A_Const
{
        NodeTag         type;
        Value           val;                    /* value (includes type info, see value.h) */
        int                     location;               /* token location, or -1 if unknown */
} A_Const;

/*
 * TypeCast - a CAST expression
 */
typedef struct TypeCast
{
        NodeTag         type;
        Node       *arg;                        /* the expression being casted */
        TypeName   *typeName;           /* the target type */
        int                     location;               /* token location, or -1 if unknown */
} TypeCast;

/*
 * CollateClause - a COLLATE expression
 */
typedef struct CollateClause
{
        NodeTag         type;
        Node       *arg;                        /* input expression */
        List       *collname;           /* possibly-qualified collation name */
        int                     location;               /* token location, or -1 if unknown */
} CollateClause;

/*
 * FuncCall - a function or aggregate invocation
 *
 * agg_order (if not NIL) indicates we saw 'foo(... ORDER BY ...)'.
 * agg_star indicates we saw a 'foo(*)' construct, while agg_distinct
 * indicates we saw 'foo(DISTINCT ...)'.  In any of these cases, the
 * construct *must* be an aggregate call.  Otherwise, it might be either an
 * aggregate or some other kind of function.  However, if OVER is present
 * it had better be an aggregate or window function.
 */
typedef struct FuncCall
{
        NodeTag         type;
        List       *funcname;           /* qualified name of function */
        List       *args;                       /* the arguments (list of exprs) */
        List       *agg_order;          /* ORDER BY (list of SortBy) */
        bool            agg_star;               /* argument was really '*' */
        bool            agg_distinct;   /* arguments were labeled DISTINCT */
        bool            func_variadic;  /* last argument was labeled VARIADIC */
        struct WindowDef *over;         /* OVER clause, if any */
        int                     location;               /* token location, or -1 if unknown */
} FuncCall;

/*
 * A_Star - '*' representing all columns of a table or compound field
 *
 * This can appear within ColumnRef.fields, A_Indirection.indirection, and
 * ResTarget.indirection lists.
 */
typedef struct A_Star
{
        NodeTag         type;
} A_Star;

/*
 * A_Indices - array subscript or slice bounds ([lidx:uidx] or [uidx])
 */
typedef struct A_Indices
{
        NodeTag         type;
        Node       *lidx;                       /* NULL if it's a single subscript */
        Node       *uidx;
} A_Indices;

/*
 * A_Indirection - select a field and/or array element from an expression
 *
 * The indirection list can contain A_Indices nodes (representing
 * subscripting), string Value nodes (representing field selection --- the
 * string value is the name of the field to select), and A_Star nodes
 * (representing selection of all fields of a composite type).
 * For example, a complex selection operation like
 *                              (foo).field1[42][7].field2
 * would be represented with a single A_Indirection node having a 4-element
 * indirection list.
 *
 * Currently, A_Star must appear only as the last list element --- the grammar
 * is responsible for enforcing this!
 */
typedef struct A_Indirection
{
        NodeTag         type;
        Node       *arg;                        /* the thing being selected from */
        List       *indirection;        /* subscripts and/or field names and/or * */
} A_Indirection;

/*
 * A_ArrayExpr - an ARRAY[] construct
 */
typedef struct A_ArrayExpr
{
        NodeTag         type;
        List       *elements;           /* array element expressions */
        int                     location;               /* token location, or -1 if unknown */
} A_ArrayExpr;

/*
 * ResTarget -
 *        result target (used in target list of pre-transformed parse trees)
 *
 * In a SELECT target list, 'name' is the column label from an
 * 'AS ColumnLabel' clause, or NULL if there was none, and 'val' is the
 * value expression itself.  The 'indirection' field is not used.
 *
 * INSERT uses ResTarget in its target-column-names list.  Here, 'name' is
 * the name of the destination column, 'indirection' stores any subscripts
 * attached to the destination, and 'val' is not used.
 *
 * In an UPDATE target list, 'name' is the name of the destination column,
 * 'indirection' stores any subscripts attached to the destination, and
 * 'val' is the expression to assign.
 *
 * See A_Indirection for more info about what can appear in 'indirection'.
 */
typedef struct ResTarget
{
        NodeTag         type;
        char       *name;                       /* column name or NULL */
        List       *indirection;        /* subscripts, field names, and '*', or NIL */
        Node       *val;                        /* the value expression to compute or assign */
        int                     location;               /* token location, or -1 if unknown */
} ResTarget;

/*
 * SortBy - for ORDER BY clause
 */
typedef struct SortBy
{
        NodeTag         type;
        Node       *node;                       /* expression to sort on */
        SortByDir       sortby_dir;             /* ASC/DESC/USING/default */
        SortByNulls sortby_nulls;       /* NULLS FIRST/LAST */
        List       *useOp;                      /* name of op to use, if SORTBY_USING */
        int                     location;               /* operator location, or -1 if none/unknown */
} SortBy;

/*
 * WindowDef - raw representation of WINDOW and OVER clauses
 *
 * For entries in a WINDOW list, "name" is the window name being defined.
 * For OVER clauses, we use "name" for the "OVER window" syntax, or "refname"
 * for the "OVER (window)" syntax, which is subtly different --- the latter
 * implies overriding the window frame clause.
 */
typedef struct WindowDef
{
        NodeTag         type;
        char       *name;                       /* window's own name */
        char       *refname;            /* referenced window name, if any */
        List       *partitionClause;    /* PARTITION BY expression list */
        List       *orderClause;        /* ORDER BY (list of SortBy) */
        int                     frameOptions;   /* frame_clause options, see below */
        Node       *startOffset;        /* expression for starting bound, if any */
        Node       *endOffset;          /* expression for ending bound, if any */
        int                     location;               /* parse location, or -1 if none/unknown */
} WindowDef;

/*
 * frameOptions is an OR of these bits.  The NONDEFAULT and BETWEEN bits are
 * used so that ruleutils.c can tell which properties were specified and
 * which were defaulted; the correct behavioral bits must be set either way.
 * The START_foo and END_foo options must come in pairs of adjacent bits for
 * the convenience of gram.y, even though some of them are useless/invalid.
 * We will need more bits (and fields) to cover the full SQL:2008 option set.
 */
#define FRAMEOPTION_NONDEFAULT                                  0x00001 /* any specified? */
#define FRAMEOPTION_RANGE                                               0x00002 /* RANGE behavior */
#define FRAMEOPTION_ROWS                                                0x00004 /* ROWS behavior */
#define FRAMEOPTION_BETWEEN                                             0x00008 /* BETWEEN given? */
#define FRAMEOPTION_START_UNBOUNDED_PRECEDING   0x00010 /* start is U. P. */
#define FRAMEOPTION_END_UNBOUNDED_PRECEDING             0x00020 /* (disallowed) */
#define FRAMEOPTION_START_UNBOUNDED_FOLLOWING   0x00040 /* (disallowed) */
#define FRAMEOPTION_END_UNBOUNDED_FOLLOWING             0x00080 /* end is U. F. */
#define FRAMEOPTION_START_CURRENT_ROW                   0x00100 /* start is C. R. */
#define FRAMEOPTION_END_CURRENT_ROW                             0x00200 /* end is C. R. */
#define FRAMEOPTION_START_VALUE_PRECEDING               0x00400 /* start is V. P. */
#define FRAMEOPTION_END_VALUE_PRECEDING                 0x00800 /* end is V. P. */
#define FRAMEOPTION_START_VALUE_FOLLOWING               0x01000 /* start is V. F. */
#define FRAMEOPTION_END_VALUE_FOLLOWING                 0x02000 /* end is V. F. */

#define FRAMEOPTION_START_VALUE \
        (FRAMEOPTION_START_VALUE_PRECEDING | FRAMEOPTION_START_VALUE_FOLLOWING)
#define FRAMEOPTION_END_VALUE \
        (FRAMEOPTION_END_VALUE_PRECEDING | FRAMEOPTION_END_VALUE_FOLLOWING)

#define FRAMEOPTION_DEFAULTS \
        (FRAMEOPTION_RANGE | FRAMEOPTION_START_UNBOUNDED_PRECEDING | \
         FRAMEOPTION_END_CURRENT_ROW)

/*
 * RangeSubselect - subquery appearing in a FROM clause
 */
typedef struct RangeSubselect
{
        NodeTag         type;
        Node       *subquery;           /* the untransformed sub-select clause */
        Alias      *alias;                      /* table alias & optional column aliases */
} RangeSubselect;

/*
 * RangeFunction - function call appearing in a FROM clause
 */
typedef struct RangeFunction
{
        NodeTag         type;
        Node       *funccallnode;       /* untransformed function call tree */
        Alias      *alias;                      /* table alias & optional column aliases */
        List       *coldeflist;         /* list of ColumnDef nodes to describe result
                                                                 * of function returning RECORD */
} RangeFunction;

/*
 * ColumnDef - column definition (used in various creates)
 *
 * If the column has a default value, we may have the value expression
 * in either "raw" form (an untransformed parse tree) or "cooked" form
 * (a post-parse-analysis, executable expression tree), depending on
 * how this ColumnDef node was created (by parsing, or by inheritance
 * from an existing relation).  We should never have both in the same node!
 *
 * Similarly, we may have a COLLATE specification in either raw form
 * (represented as a CollateClause with arg==NULL) or cooked form
 * (the collation's OID).
 *
 * The constraints list may contain a CONSTR_DEFAULT item in a raw
 * parsetree produced by gram.y, but transformCreateStmt will remove
 * the item and set raw_default instead.  CONSTR_DEFAULT items
 * should not appear in any subsequent processing.
 */
typedef struct ColumnDef
{
        NodeTag         type;
        char       *colname;            /* name of column */
        TypeName   *typeName;           /* type of column */
        int                     inhcount;               /* number of times column is inherited */
        bool            is_local;               /* column has local (non-inherited) def'n */
        bool            is_not_null;    /* NOT NULL constraint specified? */
        bool            is_from_type;   /* column definition came from table type */
        char            storage;                /* attstorage setting, or 0 for default */
        Node       *raw_default;        /* default value (untransformed parse tree) */
        Node       *cooked_default; /* default value (transformed expr tree) */
        CollateClause *collClause;      /* untransformed COLLATE spec, if any */
        Oid                     collOid;                /* collation OID (InvalidOid if not set) */
        List       *constraints;        /* other constraints on column */
        List       *fdwoptions;         /* per-column FDW options */
} ColumnDef;

/*
 * inhRelation - Relation a CREATE TABLE is to inherit attributes of
 */
typedef struct InhRelation
{
        NodeTag         type;
        RangeVar   *relation;
        bits32          options;                /* OR of CreateStmtLikeOption flags */
} InhRelation;

typedef enum CreateStmtLikeOption
{
        CREATE_TABLE_LIKE_DEFAULTS = 1 << 0,
        CREATE_TABLE_LIKE_CONSTRAINTS = 1 << 1,
        CREATE_TABLE_LIKE_INDEXES = 1 << 2,
        CREATE_TABLE_LIKE_STORAGE = 1 << 3,
        CREATE_TABLE_LIKE_COMMENTS = 1 << 4,
        CREATE_TABLE_LIKE_ALL = 0x7FFFFFFF
} CreateStmtLikeOption;

/*
 * IndexElem - index parameters (used in CREATE INDEX)
 *
 * For a plain index attribute, 'name' is the name of the table column to
 * index, and 'expr' is NULL.  For an index expression, 'name' is NULL and
 * 'expr' is the expression tree.
 */
typedef struct IndexElem
{
        NodeTag         type;
        char       *name;                       /* name of attribute to index, or NULL */
        Node       *expr;                       /* expression to index, or NULL */
        char       *indexcolname;       /* name for index column; NULL = default */
        List       *collation;          /* name of collation; NIL = default */
        List       *opclass;            /* name of desired opclass; NIL = default */
        SortByDir       ordering;               /* ASC/DESC/default */
        SortByNulls nulls_ordering; /* FIRST/LAST/default */
} IndexElem;

/*
 * DefElem - a generic "name = value" option definition
 *
 * In some contexts the name can be qualified.  Also, certain SQL commands
 * allow a SET/ADD/DROP action to be attached to option settings, so it's
 * convenient to carry a field for that too.  (Note: currently, it is our
 * practice that the grammar allows namespace and action only in statements
 * where they are relevant; C code can just ignore those fields in other
 * statements.)
 */
typedef enum DefElemAction
{
        DEFELEM_UNSPEC,                         /* no action given */
        DEFELEM_SET,
        DEFELEM_ADD,
        DEFELEM_DROP
} DefElemAction;

typedef struct DefElem
{
        NodeTag         type;
        char       *defnamespace;       /* NULL if unqualified name */
        char       *defname;
        Node       *arg;                        /* a (Value *) or a (TypeName *) */
        DefElemAction defaction;        /* unspecified action, or SET/ADD/DROP */
} DefElem;

/*
 * LockingClause - raw representation of FOR UPDATE/SHARE options
 *
 * Note: lockedRels == NIL means "all relations in query".      Otherwise it
 * is a list of RangeVar nodes.  (We use RangeVar mainly because it carries
 * a location field --- currently, parse analysis insists on unqualified
 * names in LockingClause.)
 */
typedef struct LockingClause
{
        NodeTag         type;
        List       *lockedRels;         /* FOR UPDATE or FOR SHARE relations */
        bool            forUpdate;              /* true = FOR UPDATE, false = FOR SHARE */
        bool            noWait;                 /* NOWAIT option */
} LockingClause;

/*
 * XMLSERIALIZE (in raw parse tree only)
 */
typedef struct XmlSerialize
{
        NodeTag         type;
        XmlOptionType xmloption;        /* DOCUMENT or CONTENT */
        Node       *expr;
        TypeName   *typeName;
        int                     location;               /* token location, or -1 if unknown */
} XmlSerialize;


/****************************************************************************
 *      Nodes for a Query tree
 ****************************************************************************/

/*--------------------
 * RangeTblEntry -
 *        A range table is a List of RangeTblEntry nodes.
 *
 *        A range table entry may represent a plain relation, a sub-select in
 *        FROM, or the result of a JOIN clause.  (Only explicit JOIN syntax
 *        produces an RTE, not the implicit join resulting from multiple FROM
 *        items.  This is because we only need the RTE to deal with SQL features
 *        like outer joins and join-output-column aliasing.)  Other special
 *        RTE types also exist, as indicated by RTEKind.
 *
 *        Note that we consider RTE_RELATION to cover anything that has a pg_class
 *        entry.  relkind distinguishes the sub-cases.
 *
 *        alias is an Alias node representing the AS alias-clause attached to the
 *        FROM expression, or NULL if no clause.
 *
 *        eref is the table reference name and column reference names (either
 *        real or aliases).  Note that system columns (OID etc) are not included
 *        in the column list.
 *        eref->aliasname is required to be present, and should generally be used
 *        to identify the RTE for error messages etc.
 *
 *        In RELATION RTEs, the colnames in both alias and eref are indexed by
 *        physical attribute number; this means there must be colname entries for
 *        dropped columns.      When building an RTE we insert empty strings ("") for
 *        dropped columns.      Note however that a stored rule may have nonempty
 *        colnames for columns dropped since the rule was created (and for that
 *        matter the colnames might be out of date due to column renamings).
 *        The same comments apply to FUNCTION RTEs when the function's return type
 *        is a named composite type.
 *
 *        In JOIN RTEs, the colnames in both alias and eref are one-to-one with
 *        joinaliasvars entries.  A JOIN RTE will omit columns of its inputs when
 *        those columns are known to be dropped at parse time.  Again, however,
 *        a stored rule might contain entries for columns dropped since the rule
 *        was created.  (This is only possible for columns not actually referenced
 *        in the rule.)  When loading a stored rule, we replace the joinaliasvars
 *        items for any such columns with NULL Consts.  (We can't simply delete
 *        them from the joinaliasvars list, because that would affect the attnums
 *        of Vars referencing the rest of the list.)
 *
 *        inh is TRUE for relation references that should be expanded to include
 *        inheritance children, if the rel has any.  This *must* be FALSE for
 *        RTEs other than RTE_RELATION entries.
 *
 *        inFromCl marks those range variables that are listed in the FROM clause.
 *        It's false for RTEs that are added to a query behind the scenes, such
 *        as the NEW and OLD variables for a rule, or the subqueries of a UNION.
 *        This flag is not used anymore during parsing, since the parser now uses
 *        a separate "namespace" data structure to control visibility, but it is
 *        needed by ruleutils.c to determine whether RTEs should be shown in
 *        decompiled queries.
 *
 *        requiredPerms and checkAsUser specify run-time access permissions
 *        checks to be performed at query startup.      The user must have *all*
 *        of the permissions that are OR'd together in requiredPerms (zero
 *        indicates no permissions checking).  If checkAsUser is not zero,
 *        then do the permissions checks using the access rights of that user,
 *        not the current effective user ID.  (This allows rules to act as
 *        setuid gateways.)  Permissions checks only apply to RELATION RTEs.
 *
 *        For SELECT/INSERT/UPDATE permissions, if the user doesn't have
 *        table-wide permissions then it is sufficient to have the permissions
 *        on all columns identified in selectedCols (for SELECT) and/or
 *        modifiedCols (for INSERT/UPDATE; we can tell which from the query type).
 *        selectedCols and modifiedCols are bitmapsets, which cannot have negative
 *        integer members, so we subtract FirstLowInvalidHeapAttributeNumber from
 *        column numbers before storing them in these fields.  A whole-row Var
 *        reference is represented by setting the bit for InvalidAttrNumber.
 *--------------------
 */
typedef enum RTEKind
{
        RTE_RELATION,                           /* ordinary relation reference */
        RTE_SUBQUERY,                           /* subquery in FROM */
        RTE_JOIN,                                       /* join */
        RTE_FUNCTION,                           /* function in FROM */
        RTE_VALUES,                                     /* VALUES (<exprlist>), (<exprlist>), ... */
        RTE_CTE                                         /* common table expr (WITH list element) */
} RTEKind;

typedef struct RangeTblEntry
{
        NodeTag         type;

        RTEKind         rtekind;                /* see above */

        /*
         * XXX the fields applicable to only some rte kinds should be merged into
         * a union.  I didn't do this yet because the diffs would impact a lot of
         * code that is being actively worked on.  FIXME someday.
         */

        /*
         * Fields valid for a plain relation RTE (else zero):
         */
        Oid                     relid;                  /* OID of the relation */
        char            relkind;                /* relation kind (see pg_class.relkind) */

        /*
         * Fields valid for a subquery RTE (else NULL):
         */
        Query      *subquery;           /* the sub-query */
        bool            security_barrier;       /* subquery from security_barrier view */

        /*
         * Fields valid for a join RTE (else NULL/zero):
         *
         * joinaliasvars is a list of Vars or COALESCE expressions corresponding
         * to the columns of the join result.  An alias Var referencing column K
         * of the join result can be replaced by the K'th element of joinaliasvars
         * --- but to simplify the task of reverse-listing aliases correctly, we
         * do not do that until planning time.  In a Query loaded from a stored
         * rule, it is also possible for joinaliasvars items to be NULL Consts,
         * denoting columns dropped since the rule was made.
         */
        JoinType        jointype;               /* type of join */
        List       *joinaliasvars;      /* list of alias-var expansions */

        /*
         * Fields valid for a function RTE (else NULL):
         *
         * If the function returns RECORD, funccoltypes lists the column types
         * declared in the RTE's column type specification, funccoltypmods lists
         * their declared typmods, funccolcollations their collations.  Otherwise,
         * those fields are NIL.
         */
        Node       *funcexpr;           /* expression tree for func call */
        List       *funccoltypes;       /* OID list of column type OIDs */
        List       *funccoltypmods; /* integer list of column typmods */
        List       *funccolcollations;          /* OID list of column collation OIDs */

        /*
         * Fields valid for a values RTE (else NIL):
         */
        List       *values_lists;       /* list of expression lists */
        List       *values_collations;          /* OID list of column collation OIDs */

        /*
         * Fields valid for a CTE RTE (else NULL/zero):
         */
        char       *ctename;            /* name of the WITH list item */
        Index           ctelevelsup;    /* number of query levels up */
        bool            self_reference; /* is this a recursive self-reference? */
        List       *ctecoltypes;        /* OID list of column type OIDs */
        List       *ctecoltypmods;      /* integer list of column typmods */
        List       *ctecolcollations;           /* OID list of column collation OIDs */

        /*
         * Fields valid in all RTEs:
         */
        Alias      *alias;                      /* user-written alias clause, if any */
        Alias      *eref;                       /* expanded reference names */
        bool            inh;                    /* inheritance requested? */
        bool            inFromCl;               /* present in FROM clause? */
        AclMode         requiredPerms;  /* bitmask of required access permissions */
        Oid                     checkAsUser;    /* if valid, check access as this role */
        Bitmapset  *selectedCols;       /* columns needing SELECT permission */
        Bitmapset  *modifiedCols;       /* columns needing INSERT/UPDATE permission */
} RangeTblEntry;

/*
 * SortGroupClause -
 *              representation of ORDER BY, GROUP BY, PARTITION BY,
 *              DISTINCT, DISTINCT ON items
 *
 * You might think that ORDER BY is only interested in defining ordering,
 * and GROUP/DISTINCT are only interested in defining equality.  However,
 * one way to implement grouping is to sort and then apply a "uniq"-like
 * filter.      So it's also interesting to keep track of possible sort operators
 * for GROUP/DISTINCT, and in particular to try to sort for the grouping
 * in a way that will also yield a requested ORDER BY ordering.  So we need
 * to be able to compare ORDER BY and GROUP/DISTINCT lists, which motivates
 * the decision to give them the same representation.
 *
 * tleSortGroupRef must match ressortgroupref of exactly one entry of the
 *              query's targetlist; that is the expression to be sorted or grouped by.
 * eqop is the OID of the equality operator.
 * sortop is the OID of the ordering operator (a "<" or ">" operator),
 *              or InvalidOid if not available.
 * nulls_first means about what you'd expect.  If sortop is InvalidOid
 *              then nulls_first is meaningless and should be set to false.
 * hashable is TRUE if eqop is hashable (note this condition also depends
 *              on the datatype of the input expression).
 *
 * In an ORDER BY item, all fields must be valid.  (The eqop isn't essential
 * here, but it's cheap to get it along with the sortop, and requiring it
 * to be valid eases comparisons to grouping items.)  Note that this isn't
 * actually enough information to determine an ordering: if the sortop is
 * collation-sensitive, a collation OID is needed too.  We don't store the
 * collation in SortGroupClause because it's not available at the time the
 * parser builds the SortGroupClause; instead, consult the exposed collation
 * of the referenced targetlist expression to find out what it is.
 *
 * In a grouping item, eqop must be valid.      If the eqop is a btree equality
 * operator, then sortop should be set to a compatible ordering operator.
 * We prefer to set eqop/sortop/nulls_first to match any ORDER BY item that
 * the query presents for the same tlist item.  If there is none, we just
 * use the default ordering op for the datatype.
 *
 * If the tlist item's type has a hash opclass but no btree opclass, then
 * we will set eqop to the hash equality operator, sortop to InvalidOid,
 * and nulls_first to false.  A grouping item of this kind can only be
 * implemented by hashing, and of course it'll never match an ORDER BY item.
 *
 * The hashable flag is provided since we generally have the requisite
 * information readily available when the SortGroupClause is constructed,
 * and it's relatively expensive to get it again later.  Note there is no
 * need for a "sortable" flag since OidIsValid(sortop) serves the purpose.
 *
 * A query might have both ORDER BY and DISTINCT (or DISTINCT ON) clauses.
 * In SELECT DISTINCT, the distinctClause list is as long or longer than the
 * sortClause list, while in SELECT DISTINCT ON it's typically shorter.
 * The two lists must match up to the end of the shorter one --- the parser
 * rearranges the distinctClause if necessary to make this true.  (This
 * restriction ensures that only one sort step is needed to both satisfy the
 * ORDER BY and set up for the Unique step.  This is semantically necessary
 * for DISTINCT ON, and presents no real drawback for DISTINCT.)
 */
typedef struct SortGroupClause
{
        NodeTag         type;
        Index           tleSortGroupRef;        /* reference into targetlist */
        Oid                     eqop;                   /* the equality operator ('=' op) */
        Oid                     sortop;                 /* the ordering operator ('<' op), or 0 */
        bool            nulls_first;    /* do NULLs come before normal values? */
        bool            hashable;               /* can eqop be implemented by hashing? */
} SortGroupClause;

/*
 * WindowClause -
 *              transformed representation of WINDOW and OVER clauses
 *
 * A parsed Query's windowClause list contains these structs.  "name" is set
 * if the clause originally came from WINDOW, and is NULL if it originally
 * was an OVER clause (but note that we collapse out duplicate OVERs).
 * partitionClause and orderClause are lists of SortGroupClause structs.
 * winref is an ID number referenced by WindowFunc nodes; it must be unique
 * among the members of a Query's windowClause list.
 * When refname isn't null, the partitionClause is always copied from there;
 * the orderClause might or might not be copied (see copiedOrder); the framing
 * options are never copied, per spec.
 */
typedef struct WindowClause
{
        NodeTag         type;
        char       *name;                       /* window name (NULL in an OVER clause) */
        char       *refname;            /* referenced window name, if any */
        List       *partitionClause;    /* PARTITION BY list */
        List       *orderClause;        /* ORDER BY list */
        int                     frameOptions;   /* frame_clause options, see WindowDef */
        Node       *startOffset;        /* expression for starting bound, if any */
        Node       *endOffset;          /* expression for ending bound, if any */
        Index           winref;                 /* ID referenced by window functions */
        bool            copiedOrder;    /* did we copy orderClause from refname? */
} WindowClause;

/*
 * RowMarkClause -
 *         parser output representation of FOR UPDATE/SHARE clauses
 *
 * Query.rowMarks contains a separate RowMarkClause node for each relation
 * identified as a FOR UPDATE/SHARE target.  If FOR UPDATE/SHARE is applied
 * to a subquery, we generate RowMarkClauses for all normal and subquery rels
 * in the subquery, but they are marked pushedDown = true to distinguish them
 * from clauses that were explicitly written at this query level.  Also,
 * Query.hasForUpdate tells whether there were explicit FOR UPDATE/SHARE
 * clauses in the current query level.
 */
typedef struct RowMarkClause
{
        NodeTag         type;
        Index           rti;                    /* range table index of target relation */
        bool            forUpdate;              /* true = FOR UPDATE, false = FOR SHARE */
        bool            noWait;                 /* NOWAIT option */
        bool            pushedDown;             /* pushed down from higher query level? */
} RowMarkClause;

/*
 * WithClause -
 *         representation of WITH clause
 *
 * Note: WithClause does not propagate into the Query representation;
 * but CommonTableExpr does.
 */
typedef struct WithClause
{
        NodeTag         type;
        List       *ctes;                       /* list of CommonTableExprs */
        bool            recursive;              /* true = WITH RECURSIVE */
        int                     location;               /* token location, or -1 if unknown */
} WithClause;

/*
 * CommonTableExpr -
 *         representation of WITH list element
 *
 * We don't currently support the SEARCH or CYCLE clause.
 */
typedef struct CommonTableExpr
{
        NodeTag         type;
        char       *ctename;            /* query name (never qualified) */
        List       *aliascolnames;      /* optional list of column names */
        /* SelectStmt/InsertStmt/etc before parse analysis, Query afterwards: */
        Node       *ctequery;           /* the CTE's subquery */
        int                     location;               /* token location, or -1 if unknown */
        /* These fields are set during parse analysis: */
        bool            cterecursive;   /* is this CTE actually recursive? */
        int                     cterefcount;    /* number of RTEs referencing this CTE
                                                                 * (excluding internal self-references) */
        List       *ctecolnames;        /* list of output column names */
        List       *ctecoltypes;        /* OID list of output column type OIDs */
        List       *ctecoltypmods;      /* integer list of output column typmods */
        List       *ctecolcollations;           /* OID list of column collation OIDs */
} CommonTableExpr;

/* Convenience macro to get the output tlist of a CTE's query */
#define GetCTETargetList(cte) \
        (AssertMacro(IsA((cte)->ctequery, Query)), \
         ((Query *) (cte)->ctequery)->commandType == CMD_SELECT ? \
         ((Query *) (cte)->ctequery)->targetList : \
         ((Query *) (cte)->ctequery)->returningList)


/*****************************************************************************
 *              Optimizable Statements
 *****************************************************************************/

/* ----------------------
 *              Insert Statement
 *
 * The source expression is represented by SelectStmt for both the
 * SELECT and VALUES cases.  If selectStmt is NULL, then the query
 * is INSERT ... DEFAULT VALUES.
 * ----------------------
 */
typedef struct InsertStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to insert into */
        List       *cols;                       /* optional: names of the target columns */
        Node       *selectStmt;         /* the source SELECT/VALUES, or NULL */
        List       *returningList;      /* list of expressions to return */
        WithClause *withClause;         /* WITH clause */
} InsertStmt;

/* ----------------------
 *              Delete Statement
 * ----------------------
 */
typedef struct DeleteStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to delete from */
        List       *usingClause;        /* optional using clause for more tables */
        Node       *whereClause;        /* qualifications */
        List       *returningList;      /* list of expressions to return */
        WithClause *withClause;         /* WITH clause */
} DeleteStmt;

/* ----------------------
 *              Update Statement
 * ----------------------
 */
typedef struct UpdateStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to update */
        List       *targetList;         /* the target list (of ResTarget) */
        Node       *whereClause;        /* qualifications */
        List       *fromClause;         /* optional from clause for more tables */
        List       *returningList;      /* list of expressions to return */
        WithClause *withClause;         /* WITH clause */
} UpdateStmt;

/* ----------------------
 *              Select Statement
 *
 * A "simple" SELECT is represented in the output of gram.y by a single
 * SelectStmt node; so is a VALUES construct.  A query containing set
 * operators (UNION, INTERSECT, EXCEPT) is represented by a tree of SelectStmt
 * nodes, in which the leaf nodes are component SELECTs and the internal nodes
 * represent UNION, INTERSECT, or EXCEPT operators.  Using the same node
 * type for both leaf and internal nodes allows gram.y to stick ORDER BY,
 * LIMIT, etc, clause values into a SELECT statement without worrying
 * whether it is a simple or compound SELECT.
 * ----------------------
 */
typedef enum SetOperation
{
        SETOP_NONE = 0,
        SETOP_UNION,
        SETOP_INTERSECT,
        SETOP_EXCEPT
} SetOperation;

typedef struct SelectStmt
{
        NodeTag         type;

        /*
         * These fields are used only in "leaf" SelectStmts.
         */
        List       *distinctClause; /* NULL, list of DISTINCT ON exprs, or
                                                                 * lcons(NIL,NIL) for all (SELECT DISTINCT) */
        IntoClause *intoClause;         /* target for SELECT INTO / CREATE TABLE AS */
        List       *targetList;         /* the target list (of ResTarget) */
        List       *fromClause;         /* the FROM clause */
        Node       *whereClause;        /* WHERE qualification */
        List       *groupClause;        /* GROUP BY clauses */
        Node       *havingClause;       /* HAVING conditional-expression */
        List       *windowClause;       /* WINDOW window_name AS (...), ... */
        WithClause *withClause;         /* WITH clause */

        /*
         * In a "leaf" node representing a VALUES list, the above fields are all
         * null, and instead this field is set.  Note that the elements of the
         * sublists are just expressions, without ResTarget decoration. Also note
         * that a list element can be DEFAULT (represented as a SetToDefault
         * node), regardless of the context of the VALUES list. It's up to parse
         * analysis to reject that where not valid.
         */
        List       *valuesLists;        /* untransformed list of expression lists */

        /*
         * These fields are used in both "leaf" SelectStmts and upper-level
         * SelectStmts.
         */
        List       *sortClause;         /* sort clause (a list of SortBy's) */
        Node       *limitOffset;        /* # of result tuples to skip */
        Node       *limitCount;         /* # of result tuples to return */
        List       *lockingClause;      /* FOR UPDATE (list of LockingClause's) */

        /*
         * These fields are used only in upper-level SelectStmts.
         */
        SetOperation op;                        /* type of set op */
        bool            all;                    /* ALL specified? */
        struct SelectStmt *larg;        /* left child */
        struct SelectStmt *rarg;        /* right child */
        /* Eventually add fields for CORRESPONDING spec here */
} SelectStmt;


/* ----------------------
 *              Set Operation node for post-analysis query trees
 *
 * After parse analysis, a SELECT with set operations is represented by a
 * top-level Query node containing the leaf SELECTs as subqueries in its
 * range table.  Its setOperations field shows the tree of set operations,
 * with leaf SelectStmt nodes replaced by RangeTblRef nodes, and internal
 * nodes replaced by SetOperationStmt nodes.  Information about the output
 * column types is added, too.  (Note that the child nodes do not necessarily
 * produce these types directly, but we've checked that their output types
 * can be coerced to the output column type.)  Also, if it's not UNION ALL,
 * information about the types' sort/group semantics is provided in the form
 * of a SortGroupClause list (same representation as, eg, DISTINCT).
 * The resolved common column collations are provided too; but note that if
 * it's not UNION ALL, it's okay for a column to not have a common collation,
 * so a member of the colCollations list could be InvalidOid even though the
 * column has a collatable type.
 * ----------------------
 */
typedef struct SetOperationStmt
{
        NodeTag         type;
        SetOperation op;                        /* type of set op */
        bool            all;                    /* ALL specified? */
        Node       *larg;                       /* left child */
        Node       *rarg;                       /* right child */
        /* Eventually add fields for CORRESPONDING spec here */

        /* Fields derived during parse analysis: */
        List       *colTypes;           /* OID list of output column type OIDs */
        List       *colTypmods;         /* integer list of output column typmods */
        List       *colCollations;      /* OID list of output column collation OIDs */
        List       *groupClauses;       /* a list of SortGroupClause's */
        /* groupClauses is NIL if UNION ALL, but must be set otherwise */
} SetOperationStmt;


/*****************************************************************************
 *              Other Statements (no optimizations required)
 *
 *              These are not touched by parser/analyze.c except to put them into
 *              the utilityStmt field of a Query.  This is eventually passed to
 *              ProcessUtility (by-passing rewriting and planning).  Some of the
 *              statements do need attention from parse analysis, and this is
 *              done by routines in parser/parse_utilcmd.c after ProcessUtility
 *              receives the command for execution.
 *****************************************************************************/

/*
 * When a command can act on several kinds of objects with only one
 * parse structure required, use these constants to designate the
 * object type.  Note that commands typically don't support all the types.
 */

typedef enum ObjectType
{
        OBJECT_AGGREGATE,
        OBJECT_ATTRIBUTE,                       /* type's attribute, when distinct from column */
        OBJECT_CAST,
        OBJECT_COLUMN,
        OBJECT_CONSTRAINT,
        OBJECT_COLLATION,
        OBJECT_CONVERSION,
        OBJECT_DATABASE,
        OBJECT_DOMAIN,
        OBJECT_EXTENSION,
        OBJECT_FDW,
        OBJECT_FOREIGN_SERVER,
        OBJECT_FOREIGN_TABLE,
        OBJECT_FUNCTION,
        OBJECT_INDEX,
        OBJECT_LANGUAGE,
        OBJECT_LARGEOBJECT,
        OBJECT_OPCLASS,
        OBJECT_OPERATOR,
        OBJECT_OPFAMILY,
        OBJECT_ROLE,
        OBJECT_RULE,
        OBJECT_SCHEMA,
        OBJECT_SEQUENCE,
        OBJECT_TABLE,
        OBJECT_TABLESPACE,
        OBJECT_TRIGGER,
        OBJECT_TSCONFIGURATION,
        OBJECT_TSDICTIONARY,
        OBJECT_TSPARSER,
        OBJECT_TSTEMPLATE,
        OBJECT_TYPE,
        OBJECT_VIEW
} ObjectType;

/* ----------------------
 *              Create Schema Statement
 *
 * NOTE: the schemaElts list contains raw parsetrees for component statements
 * of the schema, such as CREATE TABLE, GRANT, etc.  These are analyzed and
 * executed after the schema itself is created.
 * ----------------------
 */
typedef struct CreateSchemaStmt
{
        NodeTag         type;
        char       *schemaname;         /* the name of the schema to create */
        char       *authid;                     /* the owner of the created schema */
        List       *schemaElts;         /* schema components (list of parsenodes) */
} CreateSchemaStmt;

typedef enum DropBehavior
{
        DROP_RESTRICT,                          /* drop fails if any dependent objects */
        DROP_CASCADE                            /* remove dependent objects too */
} DropBehavior;

/* ----------------------
 *      Alter Table
 * ----------------------
 */
typedef struct AlterTableStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* table to work on */
        List       *cmds;                       /* list of subcommands */
        ObjectType      relkind;                /* type of object */
} AlterTableStmt;

typedef enum AlterTableType
{
        AT_AddColumn,                           /* add column */
        AT_AddColumnRecurse,            /* internal to commands/tablecmds.c */
        AT_AddColumnToView,                     /* implicitly via CREATE OR REPLACE VIEW */
        AT_ColumnDefault,                       /* alter column default */
        AT_DropNotNull,                         /* alter column drop not null */
        AT_SetNotNull,                          /* alter column set not null */
        AT_SetStatistics,                       /* alter column set statistics */
        AT_SetOptions,                          /* alter column set ( options ) */
        AT_ResetOptions,                        /* alter column reset ( options ) */
        AT_SetStorage,                          /* alter column set storage */
        AT_DropColumn,                          /* drop column */
        AT_DropColumnRecurse,           /* internal to commands/tablecmds.c */
        AT_AddIndex,                            /* add index */
        AT_ReAddIndex,                          /* internal to commands/tablecmds.c */
        AT_AddConstraint,                       /* add constraint */
        AT_AddConstraintRecurse,        /* internal to commands/tablecmds.c */
        AT_ValidateConstraint,          /* validate constraint */
        AT_ValidateConstraintRecurse, /* internal to commands/tablecmds.c */
        AT_ProcessedConstraint,         /* pre-processed add constraint (local in
                                                                 * parser/parse_utilcmd.c) */
        AT_AddIndexConstraint,          /* add constraint using existing index */
        AT_DropConstraint,                      /* drop constraint */
        AT_DropConstraintRecurse,       /* internal to commands/tablecmds.c */
        AT_AlterColumnType,                     /* alter column type */
        AT_AlterColumnGenericOptions,   /* alter column OPTIONS (...) */
        AT_ChangeOwner,                         /* change owner */
        AT_ClusterOn,                           /* CLUSTER ON */
        AT_DropCluster,                         /* SET WITHOUT CLUSTER */
        AT_AddOids,                                     /* SET WITH OIDS */
        AT_AddOidsRecurse,                      /* internal to commands/tablecmds.c */
        AT_DropOids,                            /* SET WITHOUT OIDS */
        AT_SetTableSpace,                       /* SET TABLESPACE */
        AT_SetRelOptions,                       /* SET (...) -- AM specific parameters */
        AT_ResetRelOptions,                     /* RESET (...) -- AM specific parameters */
        AT_ReplaceRelOptions,           /* replace reloption list in its entirety */
        AT_EnableTrig,                          /* ENABLE TRIGGER name */
        AT_EnableAlwaysTrig,            /* ENABLE ALWAYS TRIGGER name */
        AT_EnableReplicaTrig,           /* ENABLE REPLICA TRIGGER name */
        AT_DisableTrig,                         /* DISABLE TRIGGER name */
        AT_EnableTrigAll,                       /* ENABLE TRIGGER ALL */
        AT_DisableTrigAll,                      /* DISABLE TRIGGER ALL */
        AT_EnableTrigUser,                      /* ENABLE TRIGGER USER */
        AT_DisableTrigUser,                     /* DISABLE TRIGGER USER */
        AT_EnableRule,                          /* ENABLE RULE name */
        AT_EnableAlwaysRule,            /* ENABLE ALWAYS RULE name */
        AT_EnableReplicaRule,           /* ENABLE REPLICA RULE name */
        AT_DisableRule,                         /* DISABLE RULE name */
        AT_AddInherit,                          /* INHERIT parent */
        AT_DropInherit,                         /* NO INHERIT parent */
        AT_AddOf,                                       /* OF <type_name> */
        AT_DropOf,                                      /* NOT OF */
        AT_GenericOptions                       /* OPTIONS (...) */
} AlterTableType;

typedef struct AlterTableCmd    /* one subcommand of an ALTER TABLE */
{
        NodeTag         type;
        AlterTableType subtype;         /* Type of table alteration to apply */
        char       *name;                       /* column, constraint, or trigger to act on,
                                                                 * or new owner or tablespace */
        Node       *def;                        /* definition of new column, index,
                                                                 * constraint, or parent table */
        DropBehavior behavior;          /* RESTRICT or CASCADE for DROP cases */
        bool            missing_ok;             /* skip error if missing? */
} AlterTableCmd;


/* ----------------------
 *      Alter Domain
 *
 * The fields are used in different ways by the different variants of
 * this command.
 * ----------------------
 */
typedef struct AlterDomainStmt
{
        NodeTag         type;
        char            subtype;                /*------------
                                                                 *      T = alter column default
                                                                 *      N = alter column drop not null
                                                                 *      O = alter column set not null
                                                                 *      C = add constraint
                                                                 *      X = drop constraint
                                                                 *------------
                                                                 */
        List       *typeName;           /* domain to work on */
        char       *name;                       /* column or constraint name to act on */
        Node       *def;                        /* definition of default or constraint */
        DropBehavior behavior;          /* RESTRICT or CASCADE for DROP cases */
        bool            missing_ok;             /* skip error if missing? */
} AlterDomainStmt;


/* ----------------------
 *              Grant|Revoke Statement
 * ----------------------
 */
typedef enum GrantTargetType
{
        ACL_TARGET_OBJECT,                      /* grant on specific named object(s) */
        ACL_TARGET_ALL_IN_SCHEMA,       /* grant on all objects in given schema(s) */
        ACL_TARGET_DEFAULTS                     /* ALTER DEFAULT PRIVILEGES */
} GrantTargetType;

typedef enum GrantObjectType
{
        ACL_OBJECT_COLUMN,                      /* column */
        ACL_OBJECT_RELATION,            /* table, view */
        ACL_OBJECT_SEQUENCE,            /* sequence */
        ACL_OBJECT_DATABASE,            /* database */
        ACL_OBJECT_DOMAIN,                      /* domain */
        ACL_OBJECT_FDW,                         /* foreign-data wrapper */
        ACL_OBJECT_FOREIGN_SERVER,      /* foreign server */
        ACL_OBJECT_FUNCTION,            /* function */
        ACL_OBJECT_LANGUAGE,            /* procedural language */
        ACL_OBJECT_LARGEOBJECT,         /* largeobject */
        ACL_OBJECT_NAMESPACE,           /* namespace */
        ACL_OBJECT_TABLESPACE,          /* tablespace */
        ACL_OBJECT_TYPE                         /* type */
} GrantObjectType;

typedef struct GrantStmt
{
        NodeTag         type;
        bool            is_grant;               /* true = GRANT, false = REVOKE */
        GrantTargetType targtype;       /* type of the grant target */
        GrantObjectType objtype;        /* kind of object being operated on */
        List       *objects;            /* list of RangeVar nodes, FuncWithArgs nodes,
                                                                 * or plain names (as Value strings) */
        List       *privileges;         /* list of AccessPriv nodes */
        /* privileges == NIL denotes ALL PRIVILEGES */
        List       *grantees;           /* list of PrivGrantee nodes */
        bool            grant_option;   /* grant or revoke grant option */
        DropBehavior behavior;          /* drop behavior (for REVOKE) */
} GrantStmt;

typedef struct PrivGrantee
{
        NodeTag         type;
        char       *rolname;            /* if NULL then PUBLIC */
} PrivGrantee;

/*
 * Note: FuncWithArgs carries only the types of the input parameters of the
 * function.  So it is sufficient to identify an existing function, but it
 * is not enough info to define a function nor to call it.
 */
typedef struct FuncWithArgs
{
        NodeTag         type;
        List       *funcname;           /* qualified name of function */
        List       *funcargs;           /* list of Typename nodes */
} FuncWithArgs;

/*
 * An access privilege, with optional list of column names
 * priv_name == NULL denotes ALL PRIVILEGES (only used with a column list)
 * cols == NIL denotes "all columns"
 * Note that simple "ALL PRIVILEGES" is represented as a NIL list, not
 * an AccessPriv with both fields null.
 */
typedef struct AccessPriv
{
        NodeTag         type;
        char       *priv_name;          /* string name of privilege */
        List       *cols;                       /* list of Value strings */
} AccessPriv;

/* ----------------------
 *              Grant/Revoke Role Statement
 *
 * Note: because of the parsing ambiguity with the GRANT <privileges>
 * statement, granted_roles is a list of AccessPriv; the execution code
 * should complain if any column lists appear.  grantee_roles is a list
 * of role names, as Value strings.
 * ----------------------
 */
typedef struct GrantRoleStmt
{
        NodeTag         type;
        List       *granted_roles;      /* list of roles to be granted/revoked */
        List       *grantee_roles;      /* list of member roles to add/delete */
        bool            is_grant;               /* true = GRANT, false = REVOKE */
        bool            admin_opt;              /* with admin option */
        char       *grantor;            /* set grantor to other than current role */
        DropBehavior behavior;          /* drop behavior (for REVOKE) */
} GrantRoleStmt;

/* ----------------------
 *      Alter Default Privileges Statement
 * ----------------------
 */
typedef struct AlterDefaultPrivilegesStmt
{
        NodeTag         type;
        List       *options;            /* list of DefElem */
        GrantStmt  *action;                     /* GRANT/REVOKE action (with objects=NIL) */
} AlterDefaultPrivilegesStmt;

/* ----------------------
 *              Copy Statement
 *
 * We support "COPY relation FROM file", "COPY relation TO file", and
 * "COPY (query) TO file".      In any given CopyStmt, exactly one of "relation"
 * and "query" must be non-NULL.
 * ----------------------
 */
typedef struct CopyStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* the relation to copy */
        Node       *query;                      /* the SELECT query to copy */
        List       *attlist;            /* List of column names (as Strings), or NIL
                                                                 * for all columns */
        bool            is_from;                /* TO or FROM */
        char       *filename;           /* filename, or NULL for STDIN/STDOUT */
        List       *options;            /* List of DefElem nodes */
} CopyStmt;

/* ----------------------
 * SET Statement (includes RESET)
 *
 * "SET var TO DEFAULT" and "RESET var" are semantically equivalent, but we
 * preserve the distinction in VariableSetKind for CreateCommandTag().
 * ----------------------
 */
typedef enum
{
        VAR_SET_VALUE,                          /* SET var = value */
        VAR_SET_DEFAULT,                        /* SET var TO DEFAULT */
        VAR_SET_CURRENT,                        /* SET var FROM CURRENT */
        VAR_SET_MULTI,                          /* special case for SET TRANSACTION ... */
        VAR_RESET,                                      /* RESET var */
        VAR_RESET_ALL                           /* RESET ALL */
} VariableSetKind;

typedef struct VariableSetStmt
{
        NodeTag         type;
        VariableSetKind kind;
        char       *name;                       /* variable to be set */
        List       *args;                       /* List of A_Const nodes */
        bool            is_local;               /* SET LOCAL? */
} VariableSetStmt;

/* ----------------------
 * Show Statement
 * ----------------------
 */
typedef struct VariableShowStmt
{
        NodeTag         type;
        char       *name;
} VariableShowStmt;

/* ----------------------
 *              Create Table Statement
 *
 * NOTE: in the raw gram.y output, ColumnDef and Constraint nodes are
 * intermixed in tableElts, and constraints is NIL.  After parse analysis,
 * tableElts contains just ColumnDefs, and constraints contains just
 * Constraint nodes (in fact, only CONSTR_CHECK nodes, in the present
 * implementation).
 * ----------------------
 */

typedef struct CreateStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to create */
        List       *tableElts;          /* column definitions (list of ColumnDef) */
        List       *inhRelations;       /* relations to inherit from (list of
                                                                 * inhRelation) */
        TypeName   *ofTypename;         /* OF typename */
        List       *constraints;        /* constraints (list of Constraint nodes) */
        List       *options;            /* options from WITH clause */
        OnCommitAction oncommit;        /* what do we do at COMMIT? */
        char       *tablespacename; /* table space to use, or NULL */
        bool            if_not_exists;  /* just do nothing if it already exists? */
} CreateStmt;

/* ----------
 * Definitions for constraints in CreateStmt
 *
 * Note that column defaults are treated as a type of constraint,
 * even though that's a bit odd semantically.
 *
 * For constraints that use expressions (CONSTR_CHECK, CONSTR_DEFAULT)
 * we may have the expression in either "raw" form (an untransformed
 * parse tree) or "cooked" form (the nodeToString representation of
 * an executable expression tree), depending on how this Constraint
 * node was created (by parsing, or by inheritance from an existing
 * relation).  We should never have both in the same node!
 *
 * FKCONSTR_ACTION_xxx values are stored into pg_constraint.confupdtype
 * and pg_constraint.confdeltype columns; FKCONSTR_MATCH_xxx values are
 * stored into pg_constraint.confmatchtype.  Changing the code values may
 * require an initdb!
 *
 * If skip_validation is true then we skip checking that the existing rows
 * in the table satisfy the constraint, and just install the catalog entries
 * for the constraint.  A new FK constraint is marked as valid iff
 * initially_valid is true.  (Usually skip_validation and initially_valid
 * are inverses, but we can set both true if the table is known empty.)
 *
 * Constraint attributes (DEFERRABLE etc) are initially represented as
 * separate Constraint nodes for simplicity of parsing.  parse_utilcmd.c makes
 * a pass through the constraints list to insert the info into the appropriate
 * Constraint node.
 * ----------
 */

typedef enum ConstrType                 /* types of constraints */
{
        CONSTR_NULL,                            /* not SQL92, but a lot of people expect it */
        CONSTR_NOTNULL,
        CONSTR_DEFAULT,
        CONSTR_CHECK,
        CONSTR_PRIMARY,
        CONSTR_UNIQUE,
        CONSTR_EXCLUSION,
        CONSTR_FOREIGN,
        CONSTR_ATTR_DEFERRABLE,         /* attributes for previous constraint node */
        CONSTR_ATTR_NOT_DEFERRABLE,
        CONSTR_ATTR_DEFERRED,
        CONSTR_ATTR_IMMEDIATE
} ConstrType;

/* Foreign key action codes */
#define FKCONSTR_ACTION_NOACTION        'a'
#define FKCONSTR_ACTION_RESTRICT        'r'
#define FKCONSTR_ACTION_CASCADE         'c'
#define FKCONSTR_ACTION_SETNULL         'n'
#define FKCONSTR_ACTION_SETDEFAULT      'd'

/* Foreign key matchtype codes */
#define FKCONSTR_MATCH_FULL                     'f'
#define FKCONSTR_MATCH_PARTIAL          'p'
#define FKCONSTR_MATCH_UNSPECIFIED      'u'

typedef struct Constraint
{
        NodeTag         type;
        ConstrType      contype;                /* see above */

        /* Fields used for most/all constraint types: */
        char       *conname;            /* Constraint name, or NULL if unnamed */
        bool            deferrable;             /* DEFERRABLE? */
        bool            initdeferred;   /* INITIALLY DEFERRED? */
        int                     location;               /* token location, or -1 if unknown */

        /* Fields used for constraints with expressions (CHECK and DEFAULT): */
        Node       *raw_expr;           /* expr, as untransformed parse tree */
        char       *cooked_expr;        /* expr, as nodeToString representation */

        /* Fields used for unique constraints (UNIQUE and PRIMARY KEY): */
        List       *keys;                       /* String nodes naming referenced column(s) */

        /* Fields used for EXCLUSION constraints: */
        List       *exclusions;         /* list of (IndexElem, operator name) pairs */

        /* Fields used for index constraints (UNIQUE, PRIMARY KEY, EXCLUSION): */
        List       *options;            /* options from WITH clause */
        char       *indexname;          /* existing index to use; otherwise NULL */
        char       *indexspace;         /* index tablespace; NULL for default */
        /* These could be, but currently are not, used for UNIQUE/PKEY: */
        char       *access_method;      /* index access method; NULL for default */
        Node       *where_clause;       /* partial index predicate */

        /* Fields used for FOREIGN KEY constraints: */
        RangeVar   *pktable;            /* Primary key table */
        List       *fk_attrs;           /* Attributes of foreign key */
        List       *pk_attrs;           /* Corresponding attrs in PK table */
        char            fk_matchtype;   /* FULL, PARTIAL, UNSPECIFIED */
        char            fk_upd_action;  /* ON UPDATE action */
        char            fk_del_action;  /* ON DELETE action */

        /* Fields used for constraints that allow a NOT VALID specification */
        bool            skip_validation;        /* skip validation of existing rows? */
        bool            initially_valid;        /* mark the new constraint as valid? */
} Constraint;

/* ----------------------
 *              Create/Drop Table Space Statements
 * ----------------------
 */

typedef struct CreateTableSpaceStmt
{
        NodeTag         type;
        char       *tablespacename;
        char       *owner;
        char       *location;
} CreateTableSpaceStmt;

typedef struct DropTableSpaceStmt
{
        NodeTag         type;
        char       *tablespacename;
        bool            missing_ok;             /* skip error if missing? */
} DropTableSpaceStmt;

typedef struct AlterTableSpaceOptionsStmt
{
        NodeTag         type;
        char       *tablespacename;
        List       *options;
        bool            isReset;
} AlterTableSpaceOptionsStmt;

/* ----------------------
 *              Create/Alter Extension Statements
 * ----------------------
 */

typedef struct CreateExtensionStmt
{
        NodeTag         type;
        char       *extname;
        bool            if_not_exists;  /* just do nothing if it already exists? */
        List       *options;            /* List of DefElem nodes */
} CreateExtensionStmt;

/* Only used for ALTER EXTENSION UPDATE; later might need an action field */
typedef struct AlterExtensionStmt
{
        NodeTag         type;
        char       *extname;
        List       *options;            /* List of DefElem nodes */
} AlterExtensionStmt;

typedef struct AlterExtensionContentsStmt
{
        NodeTag         type;
        char       *extname;            /* Extension's name */
        int                     action;                 /* +1 = add object, -1 = drop object */
        ObjectType      objtype;                /* Object's type */
        List       *objname;            /* Qualified name of the object */
        List       *objargs;            /* Arguments if needed (eg, for functions) */
} AlterExtensionContentsStmt;

/* ----------------------
 *              Create/Alter FOREIGN DATA WRAPPER Statements
 * ----------------------
 */

typedef struct CreateFdwStmt
{
        NodeTag         type;
        char       *fdwname;            /* foreign-data wrapper name */
        List       *func_options;       /* HANDLER/VALIDATOR options */
        List       *options;            /* generic options to FDW */
} CreateFdwStmt;

typedef struct AlterFdwStmt
{
        NodeTag         type;
        char       *fdwname;            /* foreign-data wrapper name */
        List       *func_options;       /* HANDLER/VALIDATOR options */
        List       *options;            /* generic options to FDW */
} AlterFdwStmt;

/* ----------------------
 *              Create/Alter FOREIGN SERVER Statements
 * ----------------------
 */

typedef struct CreateForeignServerStmt
{
        NodeTag         type;
        char       *servername;         /* server name */
        char       *servertype;         /* optional server type */
        char       *version;            /* optional server version */
        char       *fdwname;            /* FDW name */
        List       *options;            /* generic options to server */
} CreateForeignServerStmt;

typedef struct AlterForeignServerStmt
{
        NodeTag         type;
        char       *servername;         /* server name */
        char       *version;            /* optional server version */
        List       *options;            /* generic options to server */
        bool            has_version;    /* version specified */
} AlterForeignServerStmt;

/* ----------------------
 *              Create FOREIGN TABLE Statements
 * ----------------------
 */

typedef struct CreateForeignTableStmt
{
        CreateStmt      base;
        char       *servername;
        List       *options;
} CreateForeignTableStmt;

/* ----------------------
 *              Create/Drop USER MAPPING Statements
 * ----------------------
 */

typedef struct CreateUserMappingStmt
{
        NodeTag         type;
        char       *username;           /* username or PUBLIC/CURRENT_USER */
        char       *servername;         /* server name */
        List       *options;            /* generic options to server */
} CreateUserMappingStmt;

typedef struct AlterUserMappingStmt
{
        NodeTag         type;
        char       *username;           /* username or PUBLIC/CURRENT_USER */
        char       *servername;         /* server name */
        List       *options;            /* generic options to server */
} AlterUserMappingStmt;

typedef struct DropUserMappingStmt
{
        NodeTag         type;
        char       *username;           /* username or PUBLIC/CURRENT_USER */
        char       *servername;         /* server name */
        bool            missing_ok;             /* ignore missing mappings */
} DropUserMappingStmt;

/* ----------------------
 *              Create TRIGGER Statement
 * ----------------------
 */
typedef struct CreateTrigStmt
{
        NodeTag         type;
        char       *trigname;           /* TRIGGER's name */
        RangeVar   *relation;           /* relation trigger is on */
        List       *funcname;           /* qual. name of function to call */
        List       *args;                       /* list of (T_String) Values or NIL */
        bool            row;                    /* ROW/STATEMENT */
        /* timing uses the TRIGGER_TYPE bits defined in catalog/pg_trigger.h */
        int16           timing;                 /* BEFORE, AFTER, or INSTEAD */
        /* events uses the TRIGGER_TYPE bits defined in catalog/pg_trigger.h */
        int16           events;                 /* "OR" of INSERT/UPDATE/DELETE/TRUNCATE */
        List       *columns;            /* column names, or NIL for all columns */
        Node       *whenClause;         /* qual expression, or NULL if none */
        bool            isconstraint;   /* This is a constraint trigger */
        /* The remaining fields are only used for constraint triggers */
        bool            deferrable;             /* [NOT] DEFERRABLE */
        bool            initdeferred;   /* INITIALLY {DEFERRED|IMMEDIATE} */
        RangeVar   *constrrel;          /* opposite relation, if RI trigger */
} CreateTrigStmt;

/* ----------------------
 *              Create PROCEDURAL LANGUAGE Statements
 * ----------------------
 */
typedef struct CreatePLangStmt
{
        NodeTag         type;
        bool            replace;                /* T => replace if already exists */
        char       *plname;                     /* PL name */
        List       *plhandler;          /* PL call handler function (qual. name) */
        List       *plinline;           /* optional inline function (qual. name) */
        List       *plvalidator;        /* optional validator function (qual. name) */
        bool            pltrusted;              /* PL is trusted */
} CreatePLangStmt;

/* ----------------------
 *      Create/Alter/Drop Role Statements
 *
 * Note: these node types are also used for the backwards-compatible
 * Create/Alter/Drop User/Group statements.  In the ALTER and DROP cases
 * there's really no need to distinguish what the original spelling was,
 * but for CREATE we mark the type because the defaults vary.
 * ----------------------
 */
typedef enum RoleStmtType
{
        ROLESTMT_ROLE,
        ROLESTMT_USER,
        ROLESTMT_GROUP
} RoleStmtType;

typedef struct CreateRoleStmt
{
        NodeTag         type;
        RoleStmtType stmt_type;         /* ROLE/USER/GROUP */
        char       *role;                       /* role name */
        List       *options;            /* List of DefElem nodes */
} CreateRoleStmt;

typedef struct AlterRoleStmt
{
        NodeTag         type;
        char       *role;                       /* role name */
        List       *options;            /* List of DefElem nodes */
        int                     action;                 /* +1 = add members, -1 = drop members */
} AlterRoleStmt;

typedef struct AlterRoleSetStmt
{
        NodeTag         type;
        char       *role;                       /* role name */
        char       *database;           /* database name, or NULL */
        VariableSetStmt *setstmt;       /* SET or RESET subcommand */
} AlterRoleSetStmt;

typedef struct DropRoleStmt
{
        NodeTag         type;
        List       *roles;                      /* List of roles to remove */
        bool            missing_ok;             /* skip error if a role is missing? */
} DropRoleStmt;

/* ----------------------
 *              {Create|Alter} SEQUENCE Statement
 * ----------------------
 */

typedef struct CreateSeqStmt
{
        NodeTag         type;
        RangeVar   *sequence;           /* the sequence to create */
        List       *options;
        Oid                     ownerId;                /* ID of owner, or InvalidOid for default */
} CreateSeqStmt;

typedef struct AlterSeqStmt
{
        NodeTag         type;
        RangeVar   *sequence;           /* the sequence to alter */
        List       *options;
} AlterSeqStmt;

/* ----------------------
 *              Create {Aggregate|Operator|Type} Statement
 * ----------------------
 */
typedef struct DefineStmt
{
        NodeTag         type;
        ObjectType      kind;                   /* aggregate, operator, type */
        bool            oldstyle;               /* hack to signal old CREATE AGG syntax */
        List       *defnames;           /* qualified name (list of Value strings) */
        List       *args;                       /* a list of TypeName (if needed) */
        List       *definition;         /* a list of DefElem */
} DefineStmt;

/* ----------------------
 *              Create Domain Statement
 * ----------------------
 */
typedef struct CreateDomainStmt
{
        NodeTag         type;
        List       *domainname;         /* qualified name (list of Value strings) */
        TypeName   *typeName;           /* the base type */
        CollateClause *collClause;      /* untransformed COLLATE spec, if any */
        List       *constraints;        /* constraints (list of Constraint nodes) */
} CreateDomainStmt;

/* ----------------------
 *              Create Operator Class Statement
 * ----------------------
 */
typedef struct CreateOpClassStmt
{
        NodeTag         type;
        List       *opclassname;        /* qualified name (list of Value strings) */
        List       *opfamilyname;       /* qualified name (ditto); NIL if omitted */
        char       *amname;                     /* name of index AM opclass is for */
        TypeName   *datatype;           /* datatype of indexed column */
        List       *items;                      /* List of CreateOpClassItem nodes */
        bool            isDefault;              /* Should be marked as default for type? */
} CreateOpClassStmt;

#define OPCLASS_ITEM_OPERATOR           1
#define OPCLASS_ITEM_FUNCTION           2
#define OPCLASS_ITEM_STORAGETYPE        3

typedef struct CreateOpClassItem
{
        NodeTag         type;
        int                     itemtype;               /* see codes above */
        /* fields used for an operator or function item: */
        List       *name;                       /* operator or function name */
        List       *args;                       /* argument types */
        int                     number;                 /* strategy num or support proc num */
        List       *order_family;       /* only used for ordering operators */
        List       *class_args;         /* only used for functions */
        /* fields used for a storagetype item: */
        TypeName   *storedtype;         /* datatype stored in index */
} CreateOpClassItem;

/* ----------------------
 *              Create Operator Family Statement
 * ----------------------
 */
typedef struct CreateOpFamilyStmt
{
        NodeTag         type;
        List       *opfamilyname;       /* qualified name (list of Value strings) */
        char       *amname;                     /* name of index AM opfamily is for */
} CreateOpFamilyStmt;

/* ----------------------
 *              Alter Operator Family Statement
 * ----------------------
 */
typedef struct AlterOpFamilyStmt
{
        NodeTag         type;
        List       *opfamilyname;       /* qualified name (list of Value strings) */
        char       *amname;                     /* name of index AM opfamily is for */
        bool            isDrop;                 /* ADD or DROP the items? */
        List       *items;                      /* List of CreateOpClassItem nodes */
} AlterOpFamilyStmt;

/* ----------------------
 *              Drop Table|Sequence|View|Index|Type|Domain|Conversion|Schema Statement
 * ----------------------
 */

typedef struct DropStmt
{
        NodeTag         type;
        List       *objects;            /* list of sublists of names (as Values) */
        List       *arguments;          /* list of sublists of arguments (as Values) */
        ObjectType      removeType;             /* object type */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
        bool            missing_ok;             /* skip error if object is missing? */
} DropStmt;

/* ----------------------
 *                              Truncate Table Statement
 * ----------------------
 */
typedef struct TruncateStmt
{
        NodeTag         type;
        List       *relations;          /* relations (RangeVars) to be truncated */
        bool            restart_seqs;   /* restart owned sequences? */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} TruncateStmt;

/* ----------------------
 *                              Comment On Statement
 * ----------------------
 */
typedef struct CommentStmt
{
        NodeTag         type;
        ObjectType      objtype;                /* Object's type */
        List       *objname;            /* Qualified name of the object */
        List       *objargs;            /* Arguments if needed (eg, for functions) */
        char       *comment;            /* Comment to insert, or NULL to remove */
} CommentStmt;

/* ----------------------
 *                              SECURITY LABEL Statement
 * ----------------------
 */
typedef struct SecLabelStmt
{
        NodeTag         type;
        ObjectType      objtype;                /* Object's type */
        List       *objname;            /* Qualified name of the object */
        List       *objargs;            /* Arguments if needed (eg, for functions) */
        char       *provider;           /* Label provider (or NULL) */
        char       *label;                      /* New security label to be assigned */
} SecLabelStmt;

/* ----------------------
 *              Declare Cursor Statement
 *
 * Note: the "query" field of DeclareCursorStmt is only used in the raw grammar
 * output.      After parse analysis it's set to null, and the Query points to the
 * DeclareCursorStmt, not vice versa.
 * ----------------------
 */
#define CURSOR_OPT_BINARY               0x0001  /* BINARY */
#define CURSOR_OPT_SCROLL               0x0002  /* SCROLL explicitly given */
#define CURSOR_OPT_NO_SCROLL    0x0004  /* NO SCROLL explicitly given */
#define CURSOR_OPT_INSENSITIVE  0x0008  /* INSENSITIVE */
#define CURSOR_OPT_HOLD                 0x0010  /* WITH HOLD */
/* these planner-control flags do not correspond to any SQL grammar: */
#define CURSOR_OPT_FAST_PLAN    0x0020  /* prefer fast-start plan */
#define CURSOR_OPT_GENERIC_PLAN 0x0040  /* force use of generic plan */
#define CURSOR_OPT_CUSTOM_PLAN  0x0080  /* force use of custom plan */

typedef struct DeclareCursorStmt
{
        NodeTag         type;
        char       *portalname;         /* name of the portal (cursor) */
        int                     options;                /* bitmask of options (see above) */
        Node       *query;                      /* the raw SELECT query */
} DeclareCursorStmt;

/* ----------------------
 *              Close Portal Statement
 * ----------------------
 */
typedef struct ClosePortalStmt
{
        NodeTag         type;
        char       *portalname;         /* name of the portal (cursor) */
        /* NULL means CLOSE ALL */
} ClosePortalStmt;

/* ----------------------
 *              Fetch Statement (also Move)
 * ----------------------
 */
typedef enum FetchDirection
{
        /* for these, howMany is how many rows to fetch; FETCH_ALL means ALL */
        FETCH_FORWARD,
        FETCH_BACKWARD,
        /* for these, howMany indicates a position; only one row is fetched */
        FETCH_ABSOLUTE,
        FETCH_RELATIVE
} FetchDirection;

#define FETCH_ALL       LONG_MAX

typedef struct FetchStmt
{
        NodeTag         type;
        FetchDirection direction;       /* see above */
        long            howMany;                /* number of rows, or position argument */
        char       *portalname;         /* name of portal (cursor) */
        bool            ismove;                 /* TRUE if MOVE */
} FetchStmt;

/* ----------------------
 *              Create Index Statement
 *
 * This represents creation of an index and/or an associated constraint.
 * If indexOid isn't InvalidOid, we are not creating an index, just a
 * UNIQUE/PKEY constraint using an existing index.      isconstraint must always
 * be true in this case, and the fields describing the index properties are
 * empty.
 * ----------------------
 */
typedef struct IndexStmt
{
        NodeTag         type;
        char       *idxname;            /* name of new index, or NULL for default */
        RangeVar   *relation;           /* relation to build index on */
        char       *accessMethod;       /* name of access method (eg. btree) */
        char       *tableSpace;         /* tablespace, or NULL for default */
        List       *indexParams;        /* a list of IndexElem */
        List       *options;            /* options from WITH clause */
        Node       *whereClause;        /* qualification (partial-index predicate) */
        List       *excludeOpNames; /* exclusion operator names, or NIL if none */
        Oid                     indexOid;               /* OID of an existing index, if any */
        Oid                     oldNode;                /* relfilenode of my former self */
        bool            unique;                 /* is index unique? */
        bool            primary;                /* is index on primary key? */
        bool            isconstraint;   /* is it from a CONSTRAINT clause? */
        bool            deferrable;             /* is the constraint DEFERRABLE? */
        bool            initdeferred;   /* is the constraint INITIALLY DEFERRED? */
        bool            concurrent;             /* should this be a concurrent index build? */
} IndexStmt;

/* ----------------------
 *              Create Function Statement
 * ----------------------
 */
typedef struct CreateFunctionStmt
{
        NodeTag         type;
        bool            replace;                /* T => replace if already exists */
        List       *funcname;           /* qualified name of function to create */
        List       *parameters;         /* a list of FunctionParameter */
        TypeName   *returnType;         /* the return type */
        List       *options;            /* a list of DefElem */
        List       *withClause;         /* a list of DefElem */
} CreateFunctionStmt;

typedef enum FunctionParameterMode
{
        /* the assigned enum values appear in pg_proc, don't change 'em! */
        FUNC_PARAM_IN = 'i',            /* input only */
        FUNC_PARAM_OUT = 'o',           /* output only */
        FUNC_PARAM_INOUT = 'b',         /* both */
        FUNC_PARAM_VARIADIC = 'v',      /* variadic (always input) */
        FUNC_PARAM_TABLE = 't'          /* table function output column */
} FunctionParameterMode;

typedef struct FunctionParameter
{
        NodeTag         type;
        char       *name;                       /* parameter name, or NULL if not given */
        TypeName   *argType;            /* TypeName for parameter type */
        FunctionParameterMode mode; /* IN/OUT/etc */
        Node       *defexpr;            /* raw default expr, or NULL if not given */
} FunctionParameter;

typedef struct AlterFunctionStmt
{
        NodeTag         type;
        FuncWithArgs *func;                     /* name and args of function */
        List       *actions;            /* list of DefElem */
} AlterFunctionStmt;

/* ----------------------
 *              DO Statement
 *
 * DoStmt is the raw parser output, InlineCodeBlock is the execution-time API
 * ----------------------
 */
typedef struct DoStmt
{
        NodeTag         type;
        List       *args;                       /* List of DefElem nodes */
} DoStmt;

typedef struct InlineCodeBlock
{
        NodeTag         type;
        char       *source_text;        /* source text of anonymous code block */
        Oid                     langOid;                /* OID of selected language */
        bool            langIsTrusted;  /* trusted property of the language */
} InlineCodeBlock;

/* ----------------------
 *              Alter Object Rename Statement
 * ----------------------
 */
typedef struct RenameStmt
{
        NodeTag         type;
        ObjectType      renameType;             /* OBJECT_TABLE, OBJECT_COLUMN, etc */
        ObjectType      relationType;   /* if column name, associated relation type */
        RangeVar   *relation;           /* in case it's a table */
        List       *object;                     /* in case it's some other object */
        List       *objarg;                     /* argument types, if applicable */
        char       *subname;            /* name of contained object (column, rule,
                                                                 * trigger, etc) */
        char       *newname;            /* the new name */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} RenameStmt;

/* ----------------------
 *              ALTER object SET SCHEMA Statement
 * ----------------------
 */
typedef struct AlterObjectSchemaStmt
{
        NodeTag         type;
        ObjectType objectType;          /* OBJECT_TABLE, OBJECT_TYPE, etc */
        RangeVar   *relation;           /* in case it's a table */
        List       *object;                     /* in case it's some other object */
        List       *objarg;                     /* argument types, if applicable */
        char       *addname;            /* additional name if needed */
        char       *newschema;          /* the new schema */
} AlterObjectSchemaStmt;

/* ----------------------
 *              Alter Object Owner Statement
 * ----------------------
 */
typedef struct AlterOwnerStmt
{
        NodeTag         type;
        ObjectType objectType;          /* OBJECT_TABLE, OBJECT_TYPE, etc */
        RangeVar   *relation;           /* in case it's a table */
        List       *object;                     /* in case it's some other object */
        List       *objarg;                     /* argument types, if applicable */
        char       *addname;            /* additional name if needed */
        char       *newowner;           /* the new owner */
} AlterOwnerStmt;


/* ----------------------
 *              Create Rule Statement
 * ----------------------
 */
typedef struct RuleStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation the rule is for */
        char       *rulename;           /* name of the rule */
        Node       *whereClause;        /* qualifications */
        CmdType         event;                  /* SELECT, INSERT, etc */
        bool            instead;                /* is a 'do instead'? */
        List       *actions;            /* the action statements */
        bool            replace;                /* OR REPLACE */
} RuleStmt;

/* ----------------------
 *              Notify Statement
 * ----------------------
 */
typedef struct NotifyStmt
{
        NodeTag         type;
        char       *conditionname;      /* condition name to notify */
        char       *payload;            /* the payload string, or NULL if none */
} NotifyStmt;

/* ----------------------
 *              Listen Statement
 * ----------------------
 */
typedef struct ListenStmt
{
        NodeTag         type;
        char       *conditionname;      /* condition name to listen on */
} ListenStmt;

/* ----------------------
 *              Unlisten Statement
 * ----------------------
 */
typedef struct UnlistenStmt
{
        NodeTag         type;
        char       *conditionname;      /* name to unlisten on, or NULL for all */
} UnlistenStmt;

/* ----------------------
 *              {Begin|Commit|Rollback} Transaction Statement
 * ----------------------
 */
typedef enum TransactionStmtKind
{
        TRANS_STMT_BEGIN,
        TRANS_STMT_START,                       /* semantically identical to BEGIN */
        TRANS_STMT_COMMIT,
        TRANS_STMT_ROLLBACK,
        TRANS_STMT_SAVEPOINT,
        TRANS_STMT_RELEASE,
        TRANS_STMT_ROLLBACK_TO,
        TRANS_STMT_PREPARE,
        TRANS_STMT_COMMIT_PREPARED,
        TRANS_STMT_ROLLBACK_PREPARED
} TransactionStmtKind;

typedef struct TransactionStmt
{
        NodeTag         type;
        TransactionStmtKind kind;       /* see above */
        List       *options;            /* for BEGIN/START and savepoint commands */
        char       *gid;                        /* for two-phase-commit related commands */
} TransactionStmt;

/* ----------------------
 *              Create Type Statement, composite types
 * ----------------------
 */
typedef struct CompositeTypeStmt
{
        NodeTag         type;
        RangeVar   *typevar;            /* the composite type to be created */
        List       *coldeflist;         /* list of ColumnDef nodes */
} CompositeTypeStmt;

/* ----------------------
 *              Create Type Statement, enum types
 * ----------------------
 */
typedef struct CreateEnumStmt
{
        NodeTag         type;
        List       *typeName;           /* qualified name (list of Value strings) */
        List       *vals;                       /* enum values (list of Value strings) */
} CreateEnumStmt;

/* ----------------------
 *              Create Type Statement, range types
 * ----------------------
 */
typedef struct CreateRangeStmt
{
        NodeTag         type;
        List       *typeName;           /* qualified name (list of Value strings) */
        List       *params;                     /* range parameters (list of DefElem) */
} CreateRangeStmt;

/* ----------------------
 *              Alter Type Statement, enum types
 * ----------------------
 */
typedef struct AlterEnumStmt
{
        NodeTag         type;
        List       *typeName;           /* qualified name (list of Value strings) */
        char       *newVal;                     /* new enum value's name */
        char       *newValNeighbor; /* neighboring enum value, if specified */
        bool            newValIsAfter;  /* place new enum value after neighbor? */
} AlterEnumStmt;

/* ----------------------
 *              Create View Statement
 * ----------------------
 */
typedef struct ViewStmt
{
        NodeTag         type;
        RangeVar   *view;                       /* the view to be created */
        List       *aliases;            /* target column names */
        Node       *query;                      /* the SELECT query */
        bool            replace;                /* replace an existing view? */
        List       *options;            /* options from WITH clause */
} ViewStmt;

/* ----------------------
 *              Load Statement
 * ----------------------
 */
typedef struct LoadStmt
{
        NodeTag         type;
        char       *filename;           /* file to load */
} LoadStmt;

/* ----------------------
 *              Createdb Statement
 * ----------------------
 */
typedef struct CreatedbStmt
{
        NodeTag         type;
        char       *dbname;                     /* name of database to create */
        List       *options;            /* List of DefElem nodes */
} CreatedbStmt;

/* ----------------------
 *      Alter Database
 * ----------------------
 */
typedef struct AlterDatabaseStmt
{
        NodeTag         type;
        char       *dbname;                     /* name of database to alter */
        List       *options;            /* List of DefElem nodes */
} AlterDatabaseStmt;

typedef struct AlterDatabaseSetStmt
{
        NodeTag         type;
        char       *dbname;                     /* database name */
        VariableSetStmt *setstmt;       /* SET or RESET subcommand */
} AlterDatabaseSetStmt;

/* ----------------------
 *              Dropdb Statement
 * ----------------------
 */
typedef struct DropdbStmt
{
        NodeTag         type;
        char       *dbname;                     /* database to drop */
        bool            missing_ok;             /* skip error if db is missing? */
} DropdbStmt;

/* ----------------------
 *              Cluster Statement (support pbrown's cluster index implementation)
 * ----------------------
 */
typedef struct ClusterStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation being indexed, or NULL if all */
        char       *indexname;          /* original index defined */
        bool            verbose;                /* print progress info */
} ClusterStmt;

/* ----------------------
 *              Vacuum and Analyze Statements
 *
 * Even though these are nominally two statements, it's convenient to use
 * just one node type for both.  Note that at least one of VACOPT_VACUUM
 * and VACOPT_ANALYZE must be set in options.  VACOPT_FREEZE is an internal
 * convenience for the grammar and is not examined at runtime --- the
 * freeze_min_age and freeze_table_age fields are what matter.
 * ----------------------
 */
typedef enum VacuumOption
{
        VACOPT_VACUUM = 1 << 0,         /* do VACUUM */
        VACOPT_ANALYZE = 1 << 1,        /* do ANALYZE */
        VACOPT_VERBOSE = 1 << 2,        /* print progress info */
        VACOPT_FREEZE = 1 << 3,         /* FREEZE option */
        VACOPT_FULL = 1 << 4,           /* FULL (non-concurrent) vacuum */
        VACOPT_NOWAIT = 1 << 5          /* don't wait to get lock (autovacuum only) */
} VacuumOption;

typedef struct VacuumStmt
{
        NodeTag         type;
        int                     options;                /* OR of VacuumOption flags */
        int                     freeze_min_age; /* min freeze age, or -1 to use default */
        int                     freeze_table_age;               /* age at which to scan whole table */
        RangeVar   *relation;           /* single table to process, or NULL */
        List       *va_cols;            /* list of column names, or NIL for all */
} VacuumStmt;

/* ----------------------
 *              Explain Statement
 *
 * The "query" field is either a raw parse tree (SelectStmt, InsertStmt, etc)
 * or a Query node if parse analysis has been done.  Note that rewriting and
 * planning of the query are always postponed until execution of EXPLAIN.
 * ----------------------
 */
typedef struct ExplainStmt
{
        NodeTag         type;
        Node       *query;                      /* the query (see comments above) */
        List       *options;            /* list of DefElem nodes */
} ExplainStmt;

/* ----------------------
 * Checkpoint Statement
 * ----------------------
 */
typedef struct CheckPointStmt
{
        NodeTag         type;
} CheckPointStmt;

/* ----------------------
 * Discard Statement
 * ----------------------
 */

typedef enum DiscardMode
{
        DISCARD_ALL,
        DISCARD_PLANS,
        DISCARD_TEMP
} DiscardMode;

typedef struct DiscardStmt
{
        NodeTag         type;
        DiscardMode target;
} DiscardStmt;

/* ----------------------
 *              LOCK Statement
 * ----------------------
 */
typedef struct LockStmt
{
        NodeTag         type;
        List       *relations;          /* relations to lock */
        int                     mode;                   /* lock mode */
        bool            nowait;                 /* no wait mode */
} LockStmt;

/* ----------------------
 *              SET CONSTRAINTS Statement
 * ----------------------
 */
typedef struct ConstraintsSetStmt
{
        NodeTag         type;
        List       *constraints;        /* List of names as RangeVars */
        bool            deferred;
} ConstraintsSetStmt;

/* ----------------------
 *              REINDEX Statement
 * ----------------------
 */
typedef struct ReindexStmt
{
        NodeTag         type;
        ObjectType      kind;                   /* OBJECT_INDEX, OBJECT_TABLE, OBJECT_DATABASE */
        RangeVar   *relation;           /* Table or index to reindex */
        const char *name;                       /* name of database to reindex */
        bool            do_system;              /* include system tables in database case */
        bool            do_user;                /* include user tables in database case */
} ReindexStmt;

/* ----------------------
 *              CREATE CONVERSION Statement
 * ----------------------
 */
typedef struct CreateConversionStmt
{
        NodeTag         type;
        List       *conversion_name;    /* Name of the conversion */
        char       *for_encoding_name;          /* source encoding name */
        char       *to_encoding_name;           /* destination encoding name */
        List       *func_name;          /* qualified conversion function name */
        bool            def;                    /* is this a default conversion? */
} CreateConversionStmt;

/* ----------------------
 *      CREATE CAST Statement
 * ----------------------
 */
typedef struct CreateCastStmt
{
        NodeTag         type;
        TypeName   *sourcetype;
        TypeName   *targettype;
        FuncWithArgs *func;
        CoercionContext context;
        bool            inout;
} CreateCastStmt;

/* ----------------------
 *              PREPARE Statement
 * ----------------------
 */
typedef struct PrepareStmt
{
        NodeTag         type;
        char       *name;                       /* Name of plan, arbitrary */
        List       *argtypes;           /* Types of parameters (List of TypeName) */
        Node       *query;                      /* The query itself (as a raw parsetree) */
} PrepareStmt;


/* ----------------------
 *              EXECUTE Statement
 * ----------------------
 */

typedef struct ExecuteStmt
{
        NodeTag         type;
        char       *name;                       /* The name of the plan to execute */
        IntoClause *into;                       /* Optional table to store results in */
        List       *params;                     /* Values to assign to parameters */
} ExecuteStmt;


/* ----------------------
 *              DEALLOCATE Statement
 * ----------------------
 */
typedef struct DeallocateStmt
{
        NodeTag         type;
        char       *name;                       /* The name of the plan to remove */
        /* NULL means DEALLOCATE ALL */
} DeallocateStmt;

/*
 *              DROP OWNED statement
 */
typedef struct DropOwnedStmt
{
        NodeTag         type;
        List       *roles;
        DropBehavior behavior;
} DropOwnedStmt;

/*
 *              REASSIGN OWNED statement
 */
typedef struct ReassignOwnedStmt
{
        NodeTag         type;
        List       *roles;
        char       *newrole;
} ReassignOwnedStmt;

/*
 * TS Dictionary stmts: DefineStmt, RenameStmt and DropStmt are default
 */
typedef struct AlterTSDictionaryStmt
{
        NodeTag         type;
        List       *dictname;           /* qualified name (list of Value strings) */
        List       *options;            /* List of DefElem nodes */
} AlterTSDictionaryStmt;

/*
 * TS Configuration stmts: DefineStmt, RenameStmt and DropStmt are default
 */
typedef struct AlterTSConfigurationStmt
{
        NodeTag         type;
        List       *cfgname;            /* qualified name (list of Value strings) */

        /*
         * dicts will be non-NIL if ADD/ALTER MAPPING was specified. If dicts is
         * NIL, but tokentype isn't, DROP MAPPING was specified.
         */
        List       *tokentype;          /* list of Value strings */
        List       *dicts;                      /* list of list of Value strings */
        bool            override;               /* if true - remove old variant */
        bool            replace;                /* if true - replace dictionary by another */
        bool            missing_ok;             /* for DROP - skip error if missing? */
} AlterTSConfigurationStmt;

#endif   /* PARSENODES_H */