typecmds.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	 *
	 * For backwards compatibility we allow OPAQUE in place of the actual type
	 * name; if we see this, we issue a warning and fix up the pg_proc entry.
	 */
	argList[0] = typeOid;

	procOid = LookupFuncName(procname, 1, argList, true);
	if (OidIsValid(procOid))
		return procOid;

	/* No luck, try it with OPAQUE */
	argList[0] = OPAQUEOID;

	procOid = LookupFuncName(procname, 1, argList, true);

	if (OidIsValid(procOid))
	{
		/* Found, but must complain and fix the pg_proc entry */
		ereport(WARNING,
		(errmsg("changing argument type of function %s from \"opaque\" to %s",
				NameListToString(procname), format_type_be(typeOid))));
		SetFunctionArgType(procOid, 0, typeOid);

		/*
		 * Need CommandCounterIncrement since DefineType will likely try to
		 * alter the pg_proc tuple again.
		 */
		CommandCounterIncrement();

		return procOid;
	}

	/* Use type name, not OPAQUE, in the failure message. */
	argList[0] = typeOid;

	ereport(ERROR,
			(errcode(ERRCODE_UNDEFINED_FUNCTION),
			 errmsg("function %s does not exist",
					func_signature_string(procname, 1, argList))));

	return InvalidOid;			/* keep compiler quiet */
}

static Oid
findTypeReceiveFunction(List *procname, Oid typeOid)
{
	Oid			argList[3];
	Oid			procOid;

	/*
	 * Receive functions can take a single argument of type INTERNAL, or three
	 * arguments (internal, typioparam OID, typmod).
	 */
	argList[0] = INTERNALOID;

	procOid = LookupFuncName(procname, 1, argList, true);
	if (OidIsValid(procOid))
		return procOid;

	argList[1] = OIDOID;
	argList[2] = INT4OID;

	procOid = LookupFuncName(procname, 3, argList, true);
	if (OidIsValid(procOid))
		return procOid;

	ereport(ERROR,
			(errcode(ERRCODE_UNDEFINED_FUNCTION),
			 errmsg("function %s does not exist",
					func_signature_string(procname, 1, argList))));

	return InvalidOid;			/* keep compiler quiet */
}

static Oid
findTypeSendFunction(List *procname, Oid typeOid)
{
	Oid			argList[1];
	Oid			procOid;

	/*
	 * Send functions can take a single argument of the type.
	 */
	argList[0] = typeOid;

	procOid = LookupFuncName(procname, 1, argList, true);
	if (OidIsValid(procOid))
		return procOid;

	ereport(ERROR,
			(errcode(ERRCODE_UNDEFINED_FUNCTION),
			 errmsg("function %s does not exist",
					func_signature_string(procname, 1, argList))));

	return InvalidOid;			/* keep compiler quiet */
}

static Oid
findTypeAnalyzeFunction(List *procname, Oid typeOid)
{
	Oid			argList[1];
	Oid			procOid;

	/*
	 * Analyze functions always take one INTERNAL argument and return bool.
	 */
	argList[0] = INTERNALOID;

	procOid = LookupFuncName(procname, 1, argList, true);
	if (!OidIsValid(procOid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("function %s does not exist",
						func_signature_string(procname, 1, argList))));

	if (get_func_rettype(procOid) != BOOLOID)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
			  errmsg("type analyze function %s must return type \"boolean\"",
					 NameListToString(procname))));

	return procOid;
}


/*-------------------------------------------------------------------
 * DefineCompositeType
 *
 * Create a Composite Type relation.
 * `DefineRelation' does all the work, we just provide the correct
 * arguments!
 *
 * If the relation already exists, then 'DefineRelation' will abort
 * the xact...
 *
 * DefineCompositeType returns relid for use when creating
 * an implicit composite type during function creation
 *-------------------------------------------------------------------
 */
Oid
DefineCompositeType(const RangeVar *typevar, List *coldeflist)
{
	CreateStmt *createStmt = makeNode(CreateStmt);

	if (coldeflist == NIL)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("composite type must have at least one attribute")));

	/*
	 * now set the parameters for keys/inheritance etc. All of these are
	 * uninteresting for composite types...
	 */
	createStmt->relation = (RangeVar *) typevar;
	createStmt->tableElts = coldeflist;
	createStmt->inhRelations = NIL;
	createStmt->constraints = NIL;
	createStmt->hasoids = MUST_NOT_HAVE_OIDS;
	createStmt->oncommit = ONCOMMIT_NOOP;
	createStmt->tablespacename = NULL;

	/*
	 * finally create the relation...
	 */
	return DefineRelation(createStmt, RELKIND_COMPOSITE_TYPE);
}

/*
 * AlterDomainDefault
 *
 * Routine implementing ALTER DOMAIN SET/DROP DEFAULT statements.
 */
void
AlterDomainDefault(List *names, Node *defaultRaw)
{
	TypeName   *typename;
	Oid			domainoid;
	HeapTuple	tup;
	ParseState *pstate;
	Relation	rel;
	char	   *defaultValue;
	Node	   *defaultExpr = NULL;		/* NULL if no default specified */
	Datum		new_record[Natts_pg_type];
	char		new_record_nulls[Natts_pg_type];
	char		new_record_repl[Natts_pg_type];
	HeapTuple	newtuple;
	Form_pg_type typTup;

	/* Make a TypeName so we can use standard type lookup machinery */
	typename = makeNode(TypeName);
	typename->names = names;
	typename->typmod = -1;
	typename->arrayBounds = NIL;

	/* Lock the domain in the type table */
	rel = heap_open(TypeRelationId, RowExclusiveLock);

	/* Use LookupTypeName here so that shell types can be removed. */
	domainoid = LookupTypeName(typename);
	if (!OidIsValid(domainoid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type \"%s\" does not exist",
						TypeNameToString(typename))));

	tup = SearchSysCacheCopy(TYPEOID,
							 ObjectIdGetDatum(domainoid),
							 0, 0, 0);
	if (!HeapTupleIsValid(tup))
		elog(ERROR, "cache lookup failed for type %u", domainoid);

	/* Doesn't return if user isn't allowed to alter the domain */
	domainOwnerCheck(tup, typename);

	/* Setup new tuple */
	MemSet(new_record, (Datum) 0, sizeof(new_record));
	MemSet(new_record_nulls, ' ', sizeof(new_record_nulls));
	MemSet(new_record_repl, ' ', sizeof(new_record_repl));

	/* Useful later */
	typTup = (Form_pg_type) GETSTRUCT(tup);

	/* Store the new default, if null then skip this step */
	if (defaultRaw)
	{
		/* Create a dummy ParseState for transformExpr */
		pstate = make_parsestate(NULL);

		/*
		 * Cook the colDef->raw_expr into an expression. Note: Name is
		 * strictly for error message
		 */
		defaultExpr = cookDefault(pstate, defaultRaw,
								  typTup->typbasetype,
								  typTup->typtypmod,
								  NameStr(typTup->typname));

		/*
		 * Expression must be stored as a nodeToString result, but we also
		 * require a valid textual representation (mainly to make life easier
		 * for pg_dump).
		 */
		defaultValue = deparse_expression(defaultExpr,
								deparse_context_for(NameStr(typTup->typname),
													InvalidOid),
										  false, false);

		/*
		 * Form an updated tuple with the new default and write it back.
		 */
		new_record[Anum_pg_type_typdefaultbin - 1] = DirectFunctionCall1(textin,
															 CStringGetDatum(
												 nodeToString(defaultExpr)));

		new_record_repl[Anum_pg_type_typdefaultbin - 1] = 'r';
		new_record[Anum_pg_type_typdefault - 1] = DirectFunctionCall1(textin,
											  CStringGetDatum(defaultValue));
		new_record_repl[Anum_pg_type_typdefault - 1] = 'r';
	}
	else
		/* Default is NULL, drop it */
	{
		new_record_nulls[Anum_pg_type_typdefaultbin - 1] = 'n';
		new_record_repl[Anum_pg_type_typdefaultbin - 1] = 'r';
		new_record_nulls[Anum_pg_type_typdefault - 1] = 'n';
		new_record_repl[Anum_pg_type_typdefault - 1] = 'r';
	}

	newtuple = heap_modifytuple(tup, RelationGetDescr(rel),
								new_record, new_record_nulls,
								new_record_repl);

	simple_heap_update(rel, &tup->t_self, newtuple);

	CatalogUpdateIndexes(rel, newtuple);

	/* Rebuild dependencies */
	GenerateTypeDependencies(typTup->typnamespace,
							 domainoid,
							 typTup->typrelid,
							 0, /* relation kind is n/a */
							 typTup->typowner,
							 typTup->typinput,
							 typTup->typoutput,
							 typTup->typreceive,
							 typTup->typsend,
							 typTup->typanalyze,
							 typTup->typelem,
							 typTup->typbasetype,
							 defaultExpr,
							 true);		/* Rebuild is true */

	/* Clean up */
	heap_close(rel, NoLock);
	heap_freetuple(newtuple);
}

/*
 * AlterDomainNotNull
 *
 * Routine implementing ALTER DOMAIN SET/DROP NOT NULL statements.
 */
void
AlterDomainNotNull(List *names, bool notNull)
{
	TypeName   *typename;
	Oid			domainoid;
	Relation	typrel;
	HeapTuple	tup;
	Form_pg_type typTup;

	/* Make a TypeName so we can use standard type lookup machinery */
	typename = makeNode(TypeName);
	typename->names = names;
	typename->typmod = -1;
	typename->arrayBounds = NIL;

	/* Lock the type table */
	typrel = heap_open(TypeRelationId, RowExclusiveLock);

	/* Use LookupTypeName here so that shell types can be found (why?). */
	domainoid = LookupTypeName(typename);
	if (!OidIsValid(domainoid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type \"%s\" does not exist",
						TypeNameToString(typename))));

	tup = SearchSysCacheCopy(TYPEOID,
							 ObjectIdGetDatum(domainoid),
							 0, 0, 0);
	if (!HeapTupleIsValid(tup))
		elog(ERROR, "cache lookup failed for type %u", domainoid);
	typTup = (Form_pg_type) GETSTRUCT(tup);

	/* Doesn't return if user isn't allowed to alter the domain */
	domainOwnerCheck(tup, typename);

	/* Is the domain already set to the desired constraint? */
	if (typTup->typnotnull == notNull)
	{
		heap_close(typrel, RowExclusiveLock);
		return;
	}

	/* Adding a NOT NULL constraint requires checking existing columns */
	if (notNull)
	{
		List	   *rels;
		ListCell   *rt;

		/* Fetch relation list with attributes based on this domain */
		/* ShareLock is sufficient to prevent concurrent data changes */

		rels = get_rels_with_domain(domainoid, ShareLock);

		foreach(rt, rels)
		{
			RelToCheck *rtc = (RelToCheck *) lfirst(rt);
			Relation	testrel = rtc->rel;
			TupleDesc	tupdesc = RelationGetDescr(testrel);
			HeapScanDesc scan;
			HeapTuple	tuple;

			/* Scan all tuples in this relation */
			scan = heap_beginscan(testrel, SnapshotNow, 0, NULL);
			while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
			{
				int			i;

				/* Test attributes that are of the domain */
				for (i = 0; i < rtc->natts; i++)
				{
					int			attnum = rtc->atts[i];

					if (heap_attisnull(tuple, attnum))
						ereport(ERROR,
								(errcode(ERRCODE_NOT_NULL_VIOLATION),
								 errmsg("column \"%s\" of table \"%s\" contains null values",
								NameStr(tupdesc->attrs[attnum - 1]->attname),
										RelationGetRelationName(testrel))));
				}
			}
			heap_endscan(scan);

			/* Close each rel after processing, but keep lock */
			heap_close(testrel, NoLock);
		}
	}

	/*
	 * Okay to update pg_type row.	We can scribble on typTup because it's a
	 * copy.
	 */
	typTup->typnotnull = notNull;

	simple_heap_update(typrel, &tup->t_self, tup);

	CatalogUpdateIndexes(typrel, tup);

	/* Clean up */
	heap_freetuple(tup);
	heap_close(typrel, RowExclusiveLock);
}

/*
 * AlterDomainDropConstraint
 *
 * Implements the ALTER DOMAIN DROP CONSTRAINT statement
 */
void
AlterDomainDropConstraint(List *names, const char *constrName, DropBehavior behavior)
{
	TypeName   *typename;
	Oid			domainoid;
	HeapTuple	tup;
	Relation	rel;
	Relation	conrel;
	SysScanDesc conscan;
	ScanKeyData key[1];
	HeapTuple	contup;

	/* Make a TypeName so we can use standard type lookup machinery */
	typename = makeNode(TypeName);
	typename->names = names;
	typename->typmod = -1;
	typename->arrayBounds = NIL;

	/* Lock the type table */
	rel = heap_open(TypeRelationId, RowExclusiveLock);

	/* Use LookupTypeName here so that shell types can be removed. */
	domainoid = LookupTypeName(typename);
	if (!OidIsValid(domainoid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type \"%s\" does not exist",
						TypeNameToString(typename))));

	tup = SearchSysCacheCopy(TYPEOID,
							 ObjectIdGetDatum(domainoid),
							 0, 0, 0);
	if (!HeapTupleIsValid(tup))
		elog(ERROR, "cache lookup failed for type %u", domainoid);

	/* Doesn't return if user isn't allowed to alter the domain */
	domainOwnerCheck(tup, typename);

	/* Grab an appropriate lock on the pg_constraint relation */
	conrel = heap_open(ConstraintRelationId, RowExclusiveLock);

	/* Use the index to scan only constraints of the target relation */
	ScanKeyInit(&key[0],
				Anum_pg_constraint_contypid,
				BTEqualStrategyNumber, F_OIDEQ,
				ObjectIdGetDatum(HeapTupleGetOid(tup)));

	conscan = systable_beginscan(conrel, ConstraintTypidIndexId, true,
								 SnapshotNow, 1, key);