diff options
Diffstat (limited to 'src/backend/utils/adt/ruleutils.c')
| -rw-r--r-- | src/backend/utils/adt/ruleutils.c | 114 |
1 files changed, 113 insertions, 1 deletions
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index 1a2fe54d7ac..208cbf5d31b 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -3,7 +3,7 @@ * back to source text * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.173 2004/06/18 06:13:49 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.174 2004/06/25 17:20:24 tgl Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * @@ -42,12 +42,14 @@ #include "access/genam.h" #include "catalog/catname.h" +#include "catalog/dependency.h" #include "catalog/heap.h" #include "catalog/index.h" #include "catalog/indexing.h" #include "catalog/namespace.h" #include "catalog/pg_cast.h" #include "catalog/pg_constraint.h" +#include "catalog/pg_depend.h" #include "catalog/pg_index.h" #include "catalog/pg_opclass.h" #include "catalog/pg_operator.h" @@ -1232,6 +1234,116 @@ pg_get_userbyid(PG_FUNCTION_ARGS) PG_RETURN_NAME(result); } + +/* + * pg_get_serial_sequence + * Get the name of the sequence used by a serial column, + * formatted suitably for passing to setval, nextval or currval. + */ +Datum +pg_get_serial_sequence(PG_FUNCTION_ARGS) +{ + text *tablename = PG_GETARG_TEXT_P(0); + text *columnname = PG_GETARG_TEXT_P(1); + RangeVar *tablerv; + Oid tableOid; + char *column; + AttrNumber attnum; + Oid sequenceId = InvalidOid; + Relation depRel; + ScanKeyData key[3]; + SysScanDesc scan; + HeapTuple tup; + + /* Get the OID of the table */ + tablerv = makeRangeVarFromNameList(textToQualifiedNameList(tablename, + "pg_get_serial_sequence")); + tableOid = RangeVarGetRelid(tablerv, false); + + /* Get the number of the column */ + column = DatumGetCString(DirectFunctionCall1(textout, + PointerGetDatum(columnname))); + + attnum = get_attnum(tableOid, column); + if (attnum == InvalidAttrNumber) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_COLUMN), + errmsg("column \"%s\" of relation \"%s\" does not exist", + column, tablerv->relname))); + + /* Search the dependency table for the dependent sequence */ + depRel = heap_openr(DependRelationName, AccessShareLock); + + ScanKeyInit(&key[0], + Anum_pg_depend_refclassid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(RelOid_pg_class)); + ScanKeyInit(&key[1], + Anum_pg_depend_refobjid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(tableOid)); + ScanKeyInit(&key[2], + Anum_pg_depend_refobjsubid, + BTEqualStrategyNumber, F_INT4EQ, + Int32GetDatum(attnum)); + + scan = systable_beginscan(depRel, DependReferenceIndex, true, + SnapshotNow, 3, key); + + while (HeapTupleIsValid(tup = systable_getnext(scan))) + { + Form_pg_depend deprec = (Form_pg_depend) GETSTRUCT(tup); + + /* + * We assume any internal dependency of a relation on a column + * must be what we are looking for. + */ + if (deprec->classid == RelOid_pg_class && + deprec->objsubid == 0 && + deprec->deptype == DEPENDENCY_INTERNAL) + { + sequenceId = deprec->objid; + break; + } + } + + systable_endscan(scan); + heap_close(depRel, AccessShareLock); + + if (OidIsValid(sequenceId)) + { + HeapTuple classtup; + Form_pg_class classtuple; + char *nspname; + char *result; + + /* Get the sequence's pg_class entry */ + classtup = SearchSysCache(RELOID, + ObjectIdGetDatum(sequenceId), + 0, 0, 0); + if (!HeapTupleIsValid(classtup)) + elog(ERROR, "cache lookup failed for relation %u", sequenceId); + classtuple = (Form_pg_class) GETSTRUCT(classtup); + + /* Get the namespace */ + nspname = get_namespace_name(classtuple->relnamespace); + if (!nspname) + elog(ERROR, "cache lookup failed for namespace %u", + classtuple->relnamespace); + + /* And construct the result string */ + result = quote_qualified_identifier(nspname, + NameStr(classtuple->relname)); + + ReleaseSysCache(classtup); + + PG_RETURN_TEXT_P(string_to_text(result)); + } + + PG_RETURN_NULL(); +} + + /* ---------- * deparse_expression - General utility for deparsing expressions * |