src/include/catalog/dependency.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * dependency.h
   4  *        Routines to support inter-object dependencies.
   5  *
   6  *
   7  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  * $PostgreSQL$
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #ifndef DEPENDENCY_H
  15 #define DEPENDENCY_H
  16
  17 #include "nodes/parsenodes.h"   /* for DropBehavior */
  18
  19
  20 /*
  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).
  24  *
  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:
  28  *
  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.
  34  *
  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
  38  * is dropped.
  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.
  41  *
  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
  48  * specified or not.
  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.
  51  *
  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
  56  * contain zeroes.
  57  *
  58  * Other dependency flavors may be needed in future.
  59  */
  60
  61 typedef enum DependencyType
  62 {
  63         DEPENDENCY_NORMAL = 'n',
  64         DEPENDENCY_AUTO = 'a',
  65         DEPENDENCY_INTERNAL = 'i',
  66         DEPENDENCY_PIN = 'p'
  67 } DependencyType;
  68
  69 /*
  70  * There is also a SharedDependencyType enum type that determines the exact
  71  * semantics of an entry in pg_shdepend.  Just like regular dependency entries,
  72  * any pg_shdepend entry means that the referenced object cannot be dropped
  73  * unless the dependent object is dropped at the same time.  There are some
  74  * additional rules however:
  75  *
  76  * (a) For a SHARED_DEPENDENCY_PIN entry, there is no dependent object --
  77  * rather, the referenced object is an essential part of the system.  This
  78  * applies to the initdb-created superuser.  Entries of this type are only
  79  * created by initdb; objects in this category don't need further pg_shdepend
  80  * entries if more objects come to depend on them.
  81  *
  82  * (b) a SHARED_DEPENDENCY_OWNER entry means that the referenced object is
  83  * the role owning the dependent object.  The referenced object must be
  84  * a pg_authid entry.
  85  *
  86  * (c) a SHARED_DEPENDENCY_ACL entry means that the referenced object is
  87  * a role mentioned in the ACL field of the dependent object.  The referenced
  88  * object must be a pg_authid entry.  (SHARED_DEPENDENCY_ACL entries are not
  89  * created for the owner of an object; hence two objects may be linked by
  90  * one or the other, but not both, of these dependency types.)
  91  *
  92  * SHARED_DEPENDENCY_INVALID is a value used as a parameter in internal
  93  * routines, and is not valid in the catalog itself.
  94  */
  95 typedef enum SharedDependencyType
  96 {
  97         SHARED_DEPENDENCY_PIN = 'p',
  98         SHARED_DEPENDENCY_OWNER = 'o',
  99         SHARED_DEPENDENCY_ACL = 'a',
 100         SHARED_DEPENDENCY_INVALID = 0
 101 } SharedDependencyType;
 102
 103
 104 /*
 105  * The two objects related by a dependency are identified by ObjectAddresses.
 106  */
 107 typedef struct ObjectAddress
 108 {
 109         Oid                     classId;                /* Class Id from pg_class */
 110         Oid                     objectId;               /* OID of the object */
 111         int32           objectSubId;    /* Subitem within the object (column of table) */
 112 } ObjectAddress;
 113
 114 /* expansible list of ObjectAddresses (private in dependency.c) */
 115 typedef struct ObjectAddresses ObjectAddresses;
 116
 117 /*
 118  * This enum covers all system catalogs whose OIDs can appear in
 119  * pg_depend.classId or pg_shdepend.classId.
 120  */
 121 typedef enum ObjectClass
 122 {
 123         OCLASS_CLASS,                           /* pg_class */
 124         OCLASS_PROC,                            /* pg_proc */
 125         OCLASS_TYPE,                            /* pg_type */
 126         OCLASS_CAST,                            /* pg_cast */
 127         OCLASS_CONSTRAINT,                      /* pg_constraint */
 128         OCLASS_CONVERSION,                      /* pg_conversion */
 129         OCLASS_DEFAULT,                         /* pg_attrdef */
 130         OCLASS_LANGUAGE,                        /* pg_language */
 131         OCLASS_OPERATOR,                        /* pg_operator */
 132         OCLASS_OPCLASS,                         /* pg_opclass */
 133         OCLASS_OPFAMILY,                        /* pg_opfamily */
 134         OCLASS_AMOP,                            /* pg_amop */
 135         OCLASS_AMPROC,                          /* pg_amproc */
 136         OCLASS_REWRITE,                         /* pg_rewrite */
 137         OCLASS_TRIGGER,                         /* pg_trigger */
 138         OCLASS_SCHEMA,                          /* pg_namespace */
 139         OCLASS_TSPARSER,                        /* pg_ts_parser */
 140         OCLASS_TSDICT,                          /* pg_ts_dict */
 141         OCLASS_TSTEMPLATE,                      /* pg_ts_template */
 142         OCLASS_TSCONFIG,                        /* pg_ts_config */
 143         OCLASS_ROLE,                            /* pg_authid */
 144         OCLASS_DATABASE,                        /* pg_database */
 145         OCLASS_TBLSPACE,                        /* pg_tablespace */
 146         MAX_OCLASS                                      /* MUST BE LAST */
 147 } ObjectClass;
 148
 149
 150 /* in dependency.c */
 151
 152 extern void performDeletion(const ObjectAddress *object,
 153                                 DropBehavior behavior);
 154
 155 extern void performMultipleDeletions(const ObjectAddresses *objects,
 156                                                  DropBehavior behavior);
 157
 158 extern void deleteWhatDependsOn(const ObjectAddress *object,
 159                                         bool showNotices);
 160
 161 extern void recordDependencyOnExpr(const ObjectAddress *depender,
 162                                            Node *expr, List *rtable,
 163                                            DependencyType behavior);
 164
 165 extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 166                                                                 Node *expr, Oid relId,
 167                                                                 DependencyType behavior,
 168                                                                 DependencyType self_behavior);
 169
 170 extern ObjectClass getObjectClass(const ObjectAddress *object);
 171
 172 extern char *getObjectDescription(const ObjectAddress *object);
 173
 174 extern ObjectAddresses *new_object_addresses(void);
 175
 176 extern void add_exact_object_address(const ObjectAddress *object,
 177                                                  ObjectAddresses *addrs);
 178
 179 extern bool object_address_present(const ObjectAddress *object,
 180                                            const ObjectAddresses *addrs);
 181
 182 extern void record_object_address_dependencies(const ObjectAddress *depender,
 183                                                                    ObjectAddresses *referenced,
 184                                                                    DependencyType behavior);
 185
 186 extern void free_object_addresses(ObjectAddresses *addrs);
 187
 188 /* in pg_depend.c */
 189
 190 extern void recordDependencyOn(const ObjectAddress *depender,
 191                                    const ObjectAddress *referenced,
 192                                    DependencyType behavior);
 193
 194 extern void recordMultipleDependencies(const ObjectAddress *depender,
 195                                                    const ObjectAddress *referenced,
 196                                                    int nreferenced,
 197                                                    DependencyType behavior);
 198
 199 extern long deleteDependencyRecordsFor(Oid classId, Oid objectId);
 200
 201 extern long changeDependencyFor(Oid classId, Oid objectId,
 202                                         Oid refClassId, Oid oldRefObjectId,
 203                                         Oid newRefObjectId);
 204
 205 extern bool sequenceIsOwned(Oid seqId, Oid *tableId, int32 *colId);
 206
 207 extern void markSequenceUnowned(Oid seqId);
 208
 209 extern List *getOwnedSequences(Oid relid);
 210
 211 extern Oid      get_constraint_index(Oid constraintId);
 212
 213 extern Oid      get_index_constraint(Oid indexId);
 214
 215 /* in pg_shdepend.c */
 216
 217 extern void recordSharedDependencyOn(ObjectAddress *depender,
 218                                                  ObjectAddress *referenced,
 219                                                  SharedDependencyType deptype);
 220
 221 extern void deleteSharedDependencyRecordsFor(Oid classId, Oid objectId);
 222
 223 extern void recordDependencyOnOwner(Oid classId, Oid objectId, Oid owner);
 224
 225 extern void changeDependencyOnOwner(Oid classId, Oid objectId,
 226                                                 Oid newOwnerId);
 227
 228 extern void updateAclDependencies(Oid classId, Oid objectId,
 229                                           Oid ownerId, bool isGrant,
 230                                           int noldmembers, Oid *oldmembers,
 231                                           int nnewmembers, Oid *newmembers);
 232
 233 extern bool checkSharedDependencies(Oid classId, Oid objectId,
 234                                                                         char **detail_msg, char **detail_log_msg);
 235
 236 extern void copyTemplateDependencies(Oid templateDbId, Oid newDbId);
 237
 238 extern void dropDatabaseDependencies(Oid databaseId);
 239
 240 extern void shdepDropOwned(List *relids, DropBehavior behavior);
 241
 242 extern void shdepReassignOwned(List *relids, Oid newrole);
 243
 244 #endif   /* DEPENDENCY_H */