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Add pg_describe_object function

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This function is useful to obtain textual descriptions of objects as
stored in pg_depend.
This commit is contained in:
Alvaro Herrera 2010-11-18 16:33:48 -03:00
parent 48c348f86c
commit 6cc2deb86e
5 changed files with 48 additions and 28 deletions
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12
doc/src/sgml/func.sgml
View file

@ -12847,6 +12847,11 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
<entry><type>setof oid</type></entry>
<entry>get the set of database OIDs that have objects in the tablespace</entry>
</row>
<row>
<entry><literal><function>pg_describe_object(<parameter>catalog_id</parameter>, <parameter>object_id</parameter>, <parameter>object_sub_id</parameter>)</function>)</literal></entry>
<entry><type>text</type></entry>
<entry>get description of a database object</entry>
</row>
<row>
<entry><literal><function>pg_typeof(<parameter>any</parameter>)</function></literal></entry>
<entry><type>regtype</type></entry>
@ -12940,6 +12945,13 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
<structname>pg_class</> catalogs.
</para>
<para>
<function>pg_describe_object</function> returns a description of a database
object specified by catalog OID, object OID and a (possibly zero) sub-object ID.
This is useful to determine the identity of an object as stored in the
<structname>pg_depend</structname> catalog.
</para>
<para>
<function>pg_typeof</function> returns the OID of the data type of the
value that is passed to it. This can be helpful for troubleshooting or

57
src/backend/catalog/dependency.c
View file

@ -1982,6 +1982,12 @@ free_object_addresses(ObjectAddresses *addrs)
ObjectClass
getObjectClass(const ObjectAddress *object)
{
/* only pg_class entries can have nonzero objectSubId */
if (object->classId != RelationRelationId &&
object->objectSubId != 0)
elog(ERROR, "invalid objectSubId 0 for object class %u",
object->classId);
switch (object->classId)
{
case RelationRelationId:
@ -1989,111 +1995,84 @@ getObjectClass(const ObjectAddress *object)
return OCLASS_CLASS;
case ProcedureRelationId:
Assert(object->objectSubId == 0);
return OCLASS_PROC;
case TypeRelationId:
Assert(object->objectSubId == 0);
return OCLASS_TYPE;
case CastRelationId:
Assert(object->objectSubId == 0);
return OCLASS_CAST;
case ConstraintRelationId:
Assert(object->objectSubId == 0);
return OCLASS_CONSTRAINT;
case ConversionRelationId:
Assert(object->objectSubId == 0);
return OCLASS_CONVERSION;
case AttrDefaultRelationId:
Assert(object->objectSubId == 0);
return OCLASS_DEFAULT;
case LanguageRelationId:
Assert(object->objectSubId == 0);
return OCLASS_LANGUAGE;
case LargeObjectRelationId:
Assert(object->objectSubId == 0);
return OCLASS_LARGEOBJECT;
case OperatorRelationId:
Assert(object->objectSubId == 0);
return OCLASS_OPERATOR;
case OperatorClassRelationId:
Assert(object->objectSubId == 0);
return OCLASS_OPCLASS;
case OperatorFamilyRelationId:
Assert(object->objectSubId == 0);
return OCLASS_OPFAMILY;
case AccessMethodOperatorRelationId:
Assert(object->objectSubId == 0);
return OCLASS_AMOP;
case AccessMethodProcedureRelationId:
Assert(object->objectSubId == 0);
return OCLASS_AMPROC;
case RewriteRelationId:
Assert(object->objectSubId == 0);
return OCLASS_REWRITE;
case TriggerRelationId:
Assert(object->objectSubId == 0);
return OCLASS_TRIGGER;
case NamespaceRelationId:
Assert(object->objectSubId == 0);
return OCLASS_SCHEMA;
case TSParserRelationId:
Assert(object->objectSubId == 0);
return OCLASS_TSPARSER;
case TSDictionaryRelationId:
Assert(object->objectSubId == 0);
return OCLASS_TSDICT;
case TSTemplateRelationId:
Assert(object->objectSubId == 0);
return OCLASS_TSTEMPLATE;
case TSConfigRelationId:
Assert(object->objectSubId == 0);
return OCLASS_TSCONFIG;
case AuthIdRelationId:
Assert(object->objectSubId == 0);
return OCLASS_ROLE;
case DatabaseRelationId:
Assert(object->objectSubId == 0);
return OCLASS_DATABASE;
case TableSpaceRelationId:
Assert(object->objectSubId == 0);
return OCLASS_TBLSPACE;
case ForeignDataWrapperRelationId:
Assert(object->objectSubId == 0);
return OCLASS_FDW;
case ForeignServerRelationId:
Assert(object->objectSubId == 0);
return OCLASS_FOREIGN_SERVER;
case UserMappingRelationId:
Assert(object->objectSubId == 0);
return OCLASS_USER_MAPPING;
case DefaultAclRelationId:
Assert(object->objectSubId == 0);
return OCLASS_DEFACL;
}
@ -2807,3 +2786,27 @@ getOpFamilyDescription(StringInfo buffer, Oid opfid)
ReleaseSysCache(amTup);
ReleaseSysCache(opfTup);
}
/*
* SQL-level callable version of getObjectDescription
*/
Datum
pg_describe_object(PG_FUNCTION_ARGS)
{
Oid classid = PG_GETARG_OID(0);
Oid objid = PG_GETARG_OID(1);
int32 subobjid = PG_GETARG_INT32(2);
char *description = NULL;
ObjectAddress address;
/* for "pinned" items in pg_depend, return null */
if (!OidIsValid(classid) && !OidIsValid(objid))
PG_RETURN_NULL();
address.classId = classid;
address.objectId = objid;
address.objectSubId = subobjid;
description = getObjectDescription(&address);
PG_RETURN_TEXT_P(cstring_to_text(description));
}

2
src/include/catalog/catversion.h
View file

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201011151
#define CATALOG_VERSION_NO 201011181
#endif

2
src/include/catalog/pg_proc.h
View file

@ -3333,6 +3333,8 @@ DESCR("view system lock information");
DATA(insert OID = 1065 ( pg_prepared_xact PGNSP PGUID 12 1 1000 0 f f f t t v 0 0 2249 "" "{28,25,1184,26,26}" "{o,o,o,o,o}" "{transaction,gid,prepared,ownerid,dbid}" _null_ pg_prepared_xact _null_ _null_ _null_ ));
DESCR("view two-phase transactions");
DATA(insert OID = 3537 ( pg_describe_object PGNSP PGUID 12 1 0 0 f f f t f s 3 0 25 "26 26 23" _null_ _null_ _null_ _null_ pg_describe_object _null_ _null_ _null_ ));
DATA(insert OID = 2079 ( pg_table_is_visible PGNSP PGUID 12 1 0 0 f f f t f s 1 0 16 "26" _null_ _null_ _null_ _null_ pg_table_is_visible _null_ _null_ _null_ ));
DESCR("is table visible in search path?");
DATA(insert OID = 2080 ( pg_type_is_visible PGNSP PGUID 12 1 0 0 f f f t f s 1 0 16 "26" _null_ _null_ _null_ _null_ pg_type_is_visible _null_ _null_ _null_ ));

3
src/include/utils/builtins.h
View file

@ -1045,6 +1045,9 @@ extern Datum window_nth_value(PG_FUNCTION_ARGS);
/* access/transam/twophase.c */
extern Datum pg_prepared_xact(PG_FUNCTION_ARGS);
/* catalogs/dependency.c */
extern Datum pg_describe_object(PG_FUNCTION_ARGS);
/* commands/constraint.c */
extern Datum unique_key_recheck(PG_FUNCTION_ARGS);