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   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_constraint.h
   4  *        definition of the system "constraint" relation (pg_constraint)
   5  *        along with the relation's initial contents.
   6  *
   7  *
   8  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
   9  * Portions Copyright (c) 1994, Regents of the University of California
  10  *
  11  * $Id: pg_constraint.h,v 1.2 2002/07/16 05:53:34 tgl Exp $
  12  *
  13  * NOTES
  14  *        the genbki.sh script reads this file and generates .bki
  15  *        information from the DATA() statements.
  16  *
  17  *-------------------------------------------------------------------------
  18  */
  19 #ifndef PG_CONSTRAINT_H
  20 #define PG_CONSTRAINT_H
  21
  22 /* ----------------
  23  *              postgres.h contains the system type definintions and the
  24  *              CATALOG(), BOOTSTRAP and DATA() sugar words so this file
  25  *              can be read by both genbki.sh and the C compiler.
  26  * ----------------
  27  */
  28
  29 /* ----------------
  30  *              pg_constraint definition.  cpp turns this into
  31  *              typedef struct FormData_pg_constraint
  32  * ----------------
  33  */
  34 CATALOG(pg_constraint)
  35 {
  36         /*
  37          * conname + connamespace is deliberately not unique; we allow, for
  38          * example, the same name to be used for constraints of different
  39          * relations.  This is partly for backwards compatibility with past
  40          * Postgres practice, and partly because we don't want to have to obtain
  41          * a global lock to generate a globally unique name for a nameless
  42          * constraint.  We associate a namespace with constraint names only
  43          * for SQL92 compatibility.
  44          */
  45         NameData        conname;                /* name of this constraint */
  46         Oid                     connamespace;   /* OID of namespace containing constraint */
  47         char            contype;                /* constraint type; see codes below */
  48         bool            condeferrable;  /* deferrable constraint? */
  49         bool            condeferred;    /* deferred by default? */
  50
  51         /*
  52          * conrelid and conkey are only meaningful if the constraint applies
  53          * to a specific relation (this excludes domain constraints and
  54          * assertions).  Otherwise conrelid is 0 and conkey is NULL.
  55          */
  56         Oid                     conrelid;               /* relation this constraint constrains */
  57
  58         /*
  59          * contypid links to the pg_type row for a domain if this is a domain
  60          * constraint.  Otherwise it's 0.
  61          *
  62          * For SQL-style global ASSERTIONs, both conrelid and contypid would
  63          * be zero.  This is not presently supported, however.
  64          */
  65         Oid                     contypid;               /* domain this constraint constrains */
  66
  67         /*
  68          * These fields, plus confkey, are only meaningful for a foreign-key
  69          * constraint.  Otherwise confrelid is 0 and the char fields are spaces.
  70          */
  71         Oid                     confrelid;              /* relation referenced by foreign key */
  72         char            confupdtype;    /* foreign key's ON UPDATE action */
  73         char            confdeltype;    /* foreign key's ON DELETE action */
  74         char            confmatchtype;  /* foreign key's match type */
  75
  76         /*
  77          * VARIABLE LENGTH FIELDS start here.  These fields may be NULL, too.
  78          */
  79
  80         /*
  81          * Columns of conrelid that the constraint applies to
  82          */
  83         int2            conkey[1];
  84
  85         /*
  86          * If a foreign key, the referenced columns of confrelid
  87          */
  88         int2            confkey[1];
  89
  90         /*
  91          * If a check constraint, nodeToString representation of expression
  92          */
  93         text            conbin;
  94
  95         /*
  96          * If a check constraint, source-text representation of expression
  97          */
  98         text            consrc;
  99 } FormData_pg_constraint;
 100
 101 /* ----------------
 102  *              Form_pg_constraint corresponds to a pointer to a tuple with
 103  *              the format of pg_constraint relation.
 104  * ----------------
 105  */
 106 typedef FormData_pg_constraint *Form_pg_constraint;
 107
 108 /* ----------------
 109  *              compiler constants for pg_constraint
 110  * ----------------
 111  */
 112 #define Natts_pg_constraint                                     15
 113 #define Anum_pg_constraint_conname                      1
 114 #define Anum_pg_constraint_connamespace         2
 115 #define Anum_pg_constraint_contype                      3
 116 #define Anum_pg_constraint_condeferrable        4
 117 #define Anum_pg_constraint_condeferred          5
 118 #define Anum_pg_constraint_conrelid                     6
 119 #define Anum_pg_constraint_contypid                     7
 120 #define Anum_pg_constraint_confrelid            8
 121 #define Anum_pg_constraint_confupdtype          9
 122 #define Anum_pg_constraint_confdeltype          10
 123 #define Anum_pg_constraint_confmatchtype        11
 124 #define Anum_pg_constraint_conkey                       12
 125 #define Anum_pg_constraint_confkey                      13
 126 #define Anum_pg_constraint_conbin                       14
 127 #define Anum_pg_constraint_consrc                       15
 128
 129
 130 /* Valid values for contype */
 131 #define CONSTRAINT_CHECK                        'c'
 132 #define CONSTRAINT_FOREIGN                      'f'
 133 #define CONSTRAINT_PRIMARY                      'p'
 134 #define CONSTRAINT_UNIQUE                       'u'
 135
 136 /*
 137  * Valid values for confupdtype and confdeltype are the FKCONSTR_ACTION_xxx
 138  * constants defined in parsenodes.h.  Valid values for confmatchtype are
 139  * the FKCONSTR_MATCH_xxx constants defined in parsenodes.h.
 140  */
 141
 142
 143 /*
 144  * prototypes for functions in pg_constraint.c
 145  */
 146 extern Oid      CreateConstraintEntry(const char *constraintName,
 147                                                                   Oid constraintNamespace,
 148                                                                   char constraintType,
 149                                                                   bool isDeferrable,
 150                                                                   bool isDeferred,
 151                                                                   Oid relId,
 152                                                                   const int16 *constraintKey,
 153                                                                   int constraintNKeys,
 154                                                                   Oid domainId,
 155                                                                   Oid foreignRelId,
 156                                                                   const int16 *foreignKey,
 157                                                                   int foreignNKeys,
 158                                                                   char foreignUpdateType,
 159                                                                   char foreignDeleteType,
 160                                                                   char foreignMatchType,
 161                                                                   Node *conExpr,
 162                                                                   const char *conBin,
 163                                                                   const char *conSrc);
 164
 165 extern void RemoveConstraintById(Oid conId);
 166
 167 extern bool ConstraintNameIsUsed(Oid relId, Oid relNamespace,
 168                                                                  const char *cname);
 169 extern char *GenerateConstraintName(Oid relId, Oid relNamespace,
 170                                                                         int *counter);
 171 extern bool ConstraintNameIsGenerated(const char *cname);
 172
 173 #endif   /* PG_CONSTRAINT_H */