1 /*-------------------------------------------------------------------------
4 * Routines to support inter-object dependencies.
7 * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * $PostgreSQL: pgsql/src/include/catalog/dependency.h,v 1.26 2006/08/20 21:56:16 alvherre Exp $
12 *-------------------------------------------------------------------------
17 #include "nodes/parsenodes.h" /* for DropBehavior */
21 * Precise semantics of a dependency relationship are specified by the
22 * DependencyType code (which is stored in a "char" field in pg_depend,
23 * so we assign ASCII-code values to the enumeration members).
25 * In all cases, a dependency relationship indicates that the referenced
26 * object may not be dropped without also dropping the dependent object.
27 * However, there are several subflavors:
29 * DEPENDENCY_NORMAL ('n'): normal relationship between separately-created
30 * objects. The dependent object may be dropped without affecting the
31 * referenced object. The referenced object may only be dropped by
32 * specifying CASCADE, in which case the dependent object is dropped too.
33 * Example: a table column has a normal dependency on its datatype.
35 * DEPENDENCY_AUTO ('a'): the dependent object can be dropped separately
36 * from the referenced object, and should be automatically dropped
37 * (regardless of RESTRICT or CASCADE mode) if the referenced object
39 * Example: a named constraint on a table is made auto-dependent on
40 * the table, so that it will go away if the table is dropped.
42 * DEPENDENCY_INTERNAL ('i'): the dependent object was created as part
43 * of creation of the referenced object, and is really just a part of
44 * its internal implementation. A DROP of the dependent object will be
45 * disallowed outright (we'll tell the user to issue a DROP against the
46 * referenced object, instead). A DROP of the referenced object will be
47 * propagated through to drop the dependent object whether CASCADE is
49 * Example: a trigger that's created to enforce a foreign-key constraint
50 * is made internally dependent on the constraint's pg_constraint entry.
52 * DEPENDENCY_PIN ('p'): there is no dependent object; this type of entry
53 * is a signal that the system itself depends on the referenced object,
54 * and so that object must never be deleted. Entries of this type are
55 * created only during initdb. The fields for the dependent object
58 * Other dependency flavors may be needed in future.
62 typedef enum DependencyType
64 DEPENDENCY_NORMAL = 'n',
65 DEPENDENCY_AUTO = 'a',
66 DEPENDENCY_INTERNAL = 'i',
71 * There is also a SharedDependencyType enum type that determines the exact
72 * semantics of an entry in pg_shdepend. Just like regular dependency entries,
73 * any pg_shdepend entry means that the referenced object cannot be dropped
74 * unless the dependent object is dropped at the same time. There are some
75 * additional rules however:
77 * (a) For a SHARED_DEPENDENCY_PIN entry, there is no dependent object --
78 * rather, the referenced object is an essential part of the system. This
79 * applies to the initdb-created superuser. Entries of this type are only
80 * created by initdb; objects in this category don't need further pg_shdepend
81 * entries if more objects come to depend on them.
83 * (b) a SHARED_DEPENDENCY_OWNER entry means that the referenced object is
84 * the role owning the dependent object. The referenced object must be
87 * (c) a SHARED_DEPENDENCY_ACL entry means that the referenced object is
88 * a role mentioned in the ACL field of the dependent object. The referenced
89 * object must be a pg_authid entry. (SHARED_DEPENDENCY_ACL entries are not
90 * created for the owner of an object; hence two objects may be linked by
91 * one or the other, but not both, of these dependency types.)
93 * SHARED_DEPENDENCY_INVALID is a value used as a parameter in internal
94 * routines, and is not valid in the catalog itself.
96 typedef enum SharedDependencyType
98 SHARED_DEPENDENCY_PIN = 'p',
99 SHARED_DEPENDENCY_OWNER = 'o',
100 SHARED_DEPENDENCY_ACL = 'a',
101 SHARED_DEPENDENCY_INVALID = 0
102 } SharedDependencyType;
106 * The two objects related by a dependency are identified by ObjectAddresses.
108 typedef struct ObjectAddress
110 Oid classId; /* Class Id from pg_class */
111 Oid objectId; /* OID of the object */
112 int32 objectSubId; /* Subitem within the object (column of table) */
115 /* expansible list of ObjectAddresses */
116 typedef struct ObjectAddresses ObjectAddresses;
119 * This enum covers all system catalogs whose OIDs can appear in
120 * pg_depend.classId or pg_shdepend.classId.
122 typedef enum ObjectClass
124 OCLASS_CLASS, /* pg_class */
125 OCLASS_PROC, /* pg_proc */
126 OCLASS_TYPE, /* pg_type */
127 OCLASS_CAST, /* pg_cast */
128 OCLASS_CONSTRAINT, /* pg_constraint */
129 OCLASS_CONVERSION, /* pg_conversion */
130 OCLASS_DEFAULT, /* pg_attrdef */
131 OCLASS_LANGUAGE, /* pg_language */
132 OCLASS_OPERATOR, /* pg_operator */
133 OCLASS_OPCLASS, /* pg_opclass */
134 OCLASS_REWRITE, /* pg_rewrite */
135 OCLASS_TRIGGER, /* pg_trigger */
136 OCLASS_SCHEMA, /* pg_namespace */
137 OCLASS_ROLE, /* pg_authid */
138 OCLASS_DATABASE, /* pg_database */
139 OCLASS_TBLSPACE, /* pg_tablespace */
140 MAX_OCLASS /* MUST BE LAST */
144 /* in dependency.c */
146 extern void performDeletion(const ObjectAddress *object,
147 DropBehavior behavior);
149 extern void performMultipleDeletions(const ObjectAddresses *objects,
150 DropBehavior behavior);
152 extern void deleteWhatDependsOn(const ObjectAddress *object,
155 extern void recordDependencyOnExpr(const ObjectAddress *depender,
156 Node *expr, List *rtable,
157 DependencyType behavior);
159 extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
160 Node *expr, Oid relId,
161 DependencyType behavior,
162 DependencyType self_behavior);
164 extern ObjectClass getObjectClass(const ObjectAddress *object);
166 extern char *getObjectDescription(const ObjectAddress *object);
168 extern ObjectAddresses *new_object_addresses(void);
170 extern void add_exact_object_address(const ObjectAddress *object,
171 ObjectAddresses *addrs);
173 extern bool object_address_present(const ObjectAddress *object,
174 ObjectAddresses *addrs);
176 extern void free_object_addresses(ObjectAddresses *addrs);
180 extern void recordDependencyOn(const ObjectAddress *depender,
181 const ObjectAddress *referenced,
182 DependencyType behavior);
184 extern void recordMultipleDependencies(const ObjectAddress *depender,
185 const ObjectAddress *referenced,
187 DependencyType behavior);
189 extern long deleteDependencyRecordsFor(Oid classId, Oid objectId);
191 extern long changeDependencyFor(Oid classId, Oid objectId,
192 Oid refClassId, Oid oldRefObjectId,
195 extern bool objectIsInternalDependency(Oid classId, Oid objectId);
197 /* in pg_shdepend.c */
199 extern void recordSharedDependencyOn(ObjectAddress *depender,
200 ObjectAddress *referenced,
201 SharedDependencyType deptype);
203 extern void deleteSharedDependencyRecordsFor(Oid classId, Oid objectId);
205 extern void recordDependencyOnOwner(Oid classId, Oid objectId, Oid owner);
207 extern void changeDependencyOnOwner(Oid classId, Oid objectId,
210 extern void updateAclDependencies(Oid classId, Oid objectId,
211 Oid ownerId, bool isGrant,
212 int noldmembers, Oid *oldmembers,
213 int nnewmembers, Oid *newmembers);
215 extern char *checkSharedDependencies(Oid classId, Oid objectId);
217 extern void copyTemplateDependencies(Oid templateDbId, Oid newDbId);
219 extern void dropDatabaseDependencies(Oid databaseId);
221 extern void shdepDropOwned(List *relids, DropBehavior behavior);
223 extern void shdepReassignOwned(List *relids, Oid newrole);
225 #endif /* DEPENDENCY_H */