typecmds.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	 * Since VARNOs aren't allowed in domain constraints, relation context
	 * isn't required as anything other than a shell.
	 */
	ccsrc = deparse_expression(expr,
							   deparse_context_for(domainName,
												   InvalidOid),
							   false, false);

	/*
	 * Store the constraint in pg_constraint
	 */
	CreateConstraintEntry(constr->name, /* Constraint Name */
						  domainNamespace,		/* namespace */
						  CONSTRAINT_CHECK,		/* Constraint Type */
						  false,	/* Is Deferrable */
						  false,	/* Is Deferred */
						  InvalidOid,	/* not a relation constraint */
						  NULL,
						  0,
						  domainOid,	/* domain constraint */
						  InvalidOid,	/* Foreign key fields */
						  NULL,
						  0,
						  ' ',
						  ' ',
						  ' ',
						  InvalidOid,
						  expr, /* Tree form check constraint */
						  ccbin,	/* Binary form check constraint */
						  ccsrc);		/* Source form check constraint */

	/*
	 * Return the compiled constraint expression so the calling routine can
	 * perform any additional required tests.
	 */
	return ccbin;
}

/*
 * GetDomainConstraints - get a list of the current constraints of domain
 *
 * Returns a possibly-empty list of DomainConstraintState nodes.
 *
 * This is called by the executor during plan startup for a CoerceToDomain
 * expression node.  The given constraints will be checked for each value
 * passed through the node.
 *
 * We allow this to be called for non-domain types, in which case the result
 * is always NIL.
 */
List *
GetDomainConstraints(Oid typeOid)
{
	List	   *result = NIL;
	bool		notNull = false;
	Relation	conRel;

	conRel = heap_open(ConstraintRelationId, AccessShareLock);

	for (;;)
	{
		HeapTuple	tup;
		HeapTuple	conTup;
		Form_pg_type typTup;
		ScanKeyData key[1];
		SysScanDesc scan;

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

		if (typTup->typtype != 'd')
		{
			/* Not a domain, so done */
			ReleaseSysCache(tup);
			break;
		}

		/* Test for NOT NULL Constraint */
		if (typTup->typnotnull)
			notNull = true;

		/* Look for CHECK Constraints on this domain */
		ScanKeyInit(&key[0],
					Anum_pg_constraint_contypid,
					BTEqualStrategyNumber, F_OIDEQ,
					ObjectIdGetDatum(typeOid));

		scan = systable_beginscan(conRel, ConstraintTypidIndexId, true,
								  SnapshotNow, 1, key);

		while (HeapTupleIsValid(conTup = systable_getnext(scan)))
		{
			Form_pg_constraint c = (Form_pg_constraint) GETSTRUCT(conTup);
			Datum		val;
			bool		isNull;
			Expr	   *check_expr;
			DomainConstraintState *r;

			/* Ignore non-CHECK constraints (presently, shouldn't be any) */
			if (c->contype != CONSTRAINT_CHECK)
				continue;

			/*
			 * Not expecting conbin to be NULL, but we'll test for it anyway
			 */
			val = fastgetattr(conTup, Anum_pg_constraint_conbin,
							  conRel->rd_att, &isNull);
			if (isNull)
				elog(ERROR, "domain \"%s\" constraint \"%s\" has NULL conbin",
					 NameStr(typTup->typname), NameStr(c->conname));

			check_expr = (Expr *)
				stringToNode(DatumGetCString(DirectFunctionCall1(textout,
																 val)));

			/* ExecInitExpr assumes we already fixed opfuncids */
			fix_opfuncids((Node *) check_expr);

			r = makeNode(DomainConstraintState);
			r->constrainttype = DOM_CONSTRAINT_CHECK;
			r->name = pstrdup(NameStr(c->conname));
			r->check_expr = ExecInitExpr(check_expr, NULL);

			/*
			 * use lcons() here because constraints of lower domains should be
			 * applied earlier.
			 */
			result = lcons(r, result);
		}

		systable_endscan(scan);

		/* loop to next domain in stack */
		typeOid = typTup->typbasetype;
		ReleaseSysCache(tup);
	}

	heap_close(conRel, AccessShareLock);

	/*
	 * Only need to add one NOT NULL check regardless of how many domains in
	 * the stack request it.
	 */
	if (notNull)
	{
		DomainConstraintState *r = makeNode(DomainConstraintState);

		r->constrainttype = DOM_CONSTRAINT_NOTNULL;
		r->name = pstrdup("NOT NULL");
		r->check_expr = NULL;

		/* lcons to apply the nullness check FIRST */
		result = lcons(r, result);
	}

	return result;
}

/*
 * Change the owner of a type.
 */
void
AlterTypeOwner(List *names, Oid newOwnerId)
{
	TypeName   *typename;
	Oid			typeOid;
	Relation	rel;
	HeapTuple	tup;
	Form_pg_type typTup;
	AclResult	aclresult;

	/* 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 processed (why?) */
	typeOid = LookupTypeName(typename);
	if (!OidIsValid(typeOid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type \"%s\" does not exist",
						TypeNameToString(typename))));

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

	/*
	 * If it's a composite type, we need to check that it really is a
	 * free-standing composite type, and not a table's underlying type. We
	 * want people to use ALTER TABLE not ALTER TYPE for that case.
	 */
	if (typTup->typtype == 'c' &&
		get_rel_relkind(typTup->typrelid) != RELKIND_COMPOSITE_TYPE)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("\"%s\" is a table's row type",
						TypeNameToString(typename))));

	/*
	 * If the new owner is the same as the existing owner, consider the
	 * command to have succeeded.  This is for dump restoration purposes.
	 */
	if (typTup->typowner != newOwnerId)
	{
		/* Superusers can always do it */
		if (!superuser())
		{
			/* Otherwise, must be owner of the existing object */
			if (!pg_type_ownercheck(HeapTupleGetOid(tup), GetUserId()))
				aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TYPE,
							   TypeNameToString(typename));

			/* Must be able to become new owner */
			check_is_member_of_role(GetUserId(), newOwnerId);

			/* New owner must have CREATE privilege on namespace */
			aclresult = pg_namespace_aclcheck(typTup->typnamespace,
											  newOwnerId,
											  ACL_CREATE);
			if (aclresult != ACLCHECK_OK)
				aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
							   get_namespace_name(typTup->typnamespace));
		}

		/*
		 * Modify the owner --- okay to scribble on typTup because it's a copy
		 */
		typTup->typowner = newOwnerId;

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

		CatalogUpdateIndexes(rel, tup);

		/* Update owner dependency reference */
		changeDependencyOnOwner(TypeRelationId, typeOid, newOwnerId);
	}

	/* Clean up */
	heap_close(rel, RowExclusiveLock);
}

/*
 * AlterTypeOwnerInternal - change type owner unconditionally
 *
 * This is currently only used to propagate ALTER TABLE OWNER to the
 * table's rowtype.  It assumes the caller has done all needed checks.
 */
void
AlterTypeOwnerInternal(Oid typeOid, Oid newOwnerId)
{
	Relation	rel;
	HeapTuple	tup;
	Form_pg_type typTup;

	rel = heap_open(TypeRelationId, RowExclusiveLock);

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

	/*
	 * Modify the owner --- okay to scribble on typTup because it's a copy
	 */
	typTup->typowner = newOwnerId;

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

	CatalogUpdateIndexes(rel, tup);

	/* Update owner dependency reference */
	changeDependencyOnOwner(TypeRelationId, typeOid, newOwnerId);

	/* Clean up */
	heap_close(rel, RowExclusiveLock);
}

/*
 * Execute ALTER TYPE SET SCHEMA
 */
void
AlterTypeNamespace(List *names, const char *newschema)
{
	TypeName   *typename;
	Oid			typeOid;
	Oid			nspOid;

	/* get type OID */
	typename = makeNode(TypeName);
	typename->names = names;
	typename->typmod = -1;
	typename->arrayBounds = NIL;

	typeOid = LookupTypeName(typename);

	if (!OidIsValid(typeOid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type \"%s\" does not exist",
						TypeNameToString(typename))));

	/* check permissions on type */
	if (!pg_type_ownercheck(typeOid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TYPE,
					   format_type_be(typeOid));

	/* get schema OID and check its permissions */
	nspOid = LookupCreationNamespace(newschema);

	/* and do the work */
	AlterTypeNamespaceInternal(typeOid, nspOid, true);
}

/*
 * Move specified type to new namespace.
 *
 * Caller must have already checked privileges.
 *
 * If errorOnTableType is TRUE, the function errors out if the type is
 * a table type.  ALTER TABLE has to be used to move a table to a new
 * namespace.
 */
void
AlterTypeNamespaceInternal(Oid typeOid, Oid nspOid,
						   bool errorOnTableType)
{
	Relation	rel;
	HeapTuple	tup;
	Form_pg_type typform;
	Oid			oldNspOid;
	bool		isCompositeType;

	rel = heap_open(TypeRelationId, RowExclusiveLock);

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

	oldNspOid = typform->typnamespace;

	if (oldNspOid == nspOid)
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("type %s is already in schema \"%s\"",
						format_type_be(typeOid),
						get_namespace_name(nspOid))));

	/* disallow renaming into or out of temp schemas */
	if (isAnyTempNamespace(nspOid) || isAnyTempNamespace(oldNspOid))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			errmsg("cannot move objects into or out of temporary schemas")));

	/* same for TOAST schema */
	if (nspOid == PG_TOAST_NAMESPACE || oldNspOid == PG_TOAST_NAMESPACE)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot move objects into or out of TOAST schema")));

	/* check for duplicate name (more friendly than unique-index failure) */
	if (SearchSysCacheExists(TYPENAMENSP,
							 CStringGetDatum(NameStr(typform->typname)),
							 ObjectIdGetDatum(nspOid),
							 0, 0))
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("type \"%s\" already exists in schema \"%s\"",
						NameStr(typform->typname),
						get_namespace_name(nspOid))));

	/* Detect whether type is a composite type (but not a table rowtype) */
	isCompositeType =
		(typform->typtype == 'c' &&
		 get_rel_relkind(typform->typrelid) == RELKIND_COMPOSITE_TYPE);

	/* Enforce not-table-type if requested */
	if (typform->typtype == 'c' && !isCompositeType && errorOnTableType)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("%s is a table's row type",
						format_type_be(typeOid)),
				 errhint("Use ALTER TABLE SET SCHEMA instead.")));

	/* OK, modify the pg_type row */

	/* tup is a copy, so we can scribble directly on it */
	typform->typnamespace = nspOid;

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

	/*
	 * Composite types have pg_class entries.
	 *
	 * We need to modify the pg_class tuple as well to reflect the change of
	 * schema.
	 */
	if (isCompositeType)
	{
		Relation	classRel;

		classRel = heap_open(RelationRelationId, RowExclusiveLock);

		/*
		 * The dependency on the schema is listed under the pg_class entry, so
		 * tell AlterRelationNamespaceInternal to fix it.
		 */
		AlterRelationNamespaceInternal(classRel, typform->typrelid,
									   oldNspOid, nspOid,
									   true);

		heap_close(classRel, RowExclusiveLock);

		/*
		 * Check for constraints associated with the composite type (we don't
		 * currently support this, but probably will someday).
		 */
		AlterConstraintNamespaces(typform->typrelid, oldNspOid,
								  nspOid, false);
	}
	else
	{
		/* If it's a domain, it might have constraints */
		if (typform->typtype == 'd')
			AlterConstraintNamespaces(typeOid, oldNspOid, nspOid, true);

		/*
		 * Update dependency on schema, if any --- a table rowtype has not got
		 * one.
		 */
		if (typform->typtype != 'c')
			if (changeDependencyFor(TypeRelationId, typeOid,
								NamespaceRelationId, oldNspOid, nspOid) != 1)
				elog(ERROR, "failed to change schema dependency for type %s",
					 format_type_be(typeOid));
	}

	heap_freetuple(tup);

	heap_close(rel, RowExclusiveLock);
}