tablecmds.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,338 行 · 第 1/5 页

		recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL);

		/*
		 * Mark the parent as having subclasses.
		 */
		setRelhassubclassInRelation(parentOid, true);

		seqNumber += 1;
	}

	heap_close(relation, RowExclusiveLock);
}

/*
 * Look for an existing schema entry with the given name.
 *
 * Returns the index (starting with 1) if attribute already exists in schema,
 * 0 if it doesn't.
 */
static int
findAttrByName(const char *attributeName, List *schema)
{
	List	   *s;
	int			i = 0;

	foreach(s, schema)
	{
		ColumnDef  *def = lfirst(s);

		++i;
		if (strcmp(attributeName, def->colname) == 0)
			return i;
	}
	return 0;
}

/*
 * Update a relation's pg_class.relhassubclass entry to the given value
 */
static void
setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
{
	Relation	relationRelation;
	HeapTuple	tuple;
	Form_pg_class classtuple;

	/*
	 * Fetch a modifiable copy of the tuple, modify it, update pg_class.
	 *
	 * If the tuple already has the right relhassubclass setting, we
	 * don't need to update it, but we still need to issue an SI inval
	 * message.
	 */
	relationRelation = heap_openr(RelationRelationName, RowExclusiveLock);
	tuple = SearchSysCacheCopy(RELOID,
							   ObjectIdGetDatum(relationId),
							   0, 0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "cache lookup failed for relation %u", relationId);
	classtuple = (Form_pg_class) GETSTRUCT(tuple);

	if (classtuple->relhassubclass != relhassubclass)
	{
		classtuple->relhassubclass = relhassubclass;
		simple_heap_update(relationRelation, &tuple->t_self, tuple);

		/* keep the catalog indexes up to date */
		CatalogUpdateIndexes(relationRelation, tuple);
	}
	else
	{
		/* no need to change tuple, but force relcache rebuild anyway */
		CacheInvalidateRelcache(relationId);
	}

	heap_freetuple(tuple);
	heap_close(relationRelation, RowExclusiveLock);
}


/*
 *		renameatt		- changes the name of a attribute in a relation
 *
 *		Attname attribute is changed in attribute catalog.
 *		No record of the previous attname is kept (correct?).
 *
 *		get proper relrelation from relation catalog (if not arg)
 *		scan attribute catalog
 *				for name conflict (within rel)
 *				for original attribute (if not arg)
 *		modify attname in attribute tuple
 *		insert modified attribute in attribute catalog
 *		delete original attribute from attribute catalog
 */
void
renameatt(Oid myrelid,
		  const char *oldattname,
		  const char *newattname,
		  bool recurse,
		  bool recursing)
{
	Relation	targetrelation;
	Relation	attrelation;
	HeapTuple	atttup;
	Form_pg_attribute attform;
	int			attnum;
	List	   *indexoidlist;
	List	   *indexoidscan;

	/*
	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
	targetrelation = relation_open(myrelid, AccessExclusiveLock);

	/*
	 * permissions checking.  this would normally be done in utility.c,
	 * but this particular routine is recursive.
	 *
	 * normally, only the owner of a class can change its schema.
	 */
	if (!pg_class_ownercheck(myrelid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   RelationGetRelationName(targetrelation));
	if (!allowSystemTableMods && IsSystemRelation(targetrelation))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("permission denied: \"%s\" is a system catalog",
						RelationGetRelationName(targetrelation))));

	/*
	 * if the 'recurse' flag is set then we are supposed to rename this
	 * attribute in all classes that inherit from 'relname' (as well as in
	 * 'relname').
	 *
	 * any permissions or problems with duplicate attributes will cause the
	 * whole transaction to abort, which is what we want -- all or
	 * nothing.
	 */
	if (recurse)
	{
		List	   *child,
				   *children;

		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);

		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsto(child);

			if (childrelid == myrelid)
				continue;
			/* note we need not recurse again! */
			renameatt(childrelid, oldattname, newattname, false, true);
		}
	}
	else
	{
		/*
		 * If we are told not to recurse, there had better not be any
		 * child tables; else the rename would put them out of step.
		 */
		if (!recursing &&
			find_inheritance_children(myrelid) != NIL)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
					 errmsg("inherited column \"%s\" must be renamed in child tables too",
							oldattname)));
	}

	attrelation = heap_openr(AttributeRelationName, RowExclusiveLock);

	atttup = SearchSysCacheCopyAttName(myrelid, oldattname);
	if (!HeapTupleIsValid(atttup))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_COLUMN),
				 errmsg("column \"%s\" does not exist",
						oldattname)));
	attform = (Form_pg_attribute) GETSTRUCT(atttup);

	attnum = attform->attnum;
	if (attnum < 0)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot rename system column \"%s\"",
						oldattname)));

	/*
	 * if the attribute is inherited, forbid the renaming, unless we are
	 * already inside a recursive rename.
	 */
	if (attform->attinhcount > 0 && !recursing)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
				 errmsg("cannot rename inherited column \"%s\"",
						oldattname)));

	/* should not already exist */
	/* this test is deliberately not attisdropped-aware */
	if (SearchSysCacheExists(ATTNAME,
							 ObjectIdGetDatum(myrelid),
							 PointerGetDatum(newattname),
							 0, 0))
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_COLUMN),
			 errmsg("column \"%s\" of relation \"%s\" already exists",
				  newattname, RelationGetRelationName(targetrelation))));

	namestrcpy(&(attform->attname), newattname);

	simple_heap_update(attrelation, &atttup->t_self, atttup);

	/* keep system catalog indexes current */
	CatalogUpdateIndexes(attrelation, atttup);

	heap_freetuple(atttup);

	/*
	 * Update column names of indexes that refer to the column being
	 * renamed.
	 */
	indexoidlist = RelationGetIndexList(targetrelation);

	foreach(indexoidscan, indexoidlist)
	{
		Oid			indexoid = lfirsto(indexoidscan);
		HeapTuple	indextup;
		Form_pg_index indexform;
		int			i;

		/*
		 * Scan through index columns to see if there's any simple index
		 * entries for this attribute.	We ignore expressional entries.
		 */
		indextup = SearchSysCache(INDEXRELID,
								  ObjectIdGetDatum(indexoid),
								  0, 0, 0);
		if (!HeapTupleIsValid(indextup))
			elog(ERROR, "cache lookup failed for index %u", indexoid);
		indexform = (Form_pg_index) GETSTRUCT(indextup);

		for (i = 0; i < indexform->indnatts; i++)
		{
			if (attnum != indexform->indkey[i])
				continue;

			/*
			 * Found one, rename it.
			 */
			atttup = SearchSysCacheCopy(ATTNUM,
										ObjectIdGetDatum(indexoid),
										Int16GetDatum(i + 1),
										0, 0);
			if (!HeapTupleIsValid(atttup))
				continue;		/* should we raise an error? */

			/*
			 * Update the (copied) attribute tuple.
			 */
			namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
					   newattname);

			simple_heap_update(attrelation, &atttup->t_self, atttup);

			/* keep system catalog indexes current */
			CatalogUpdateIndexes(attrelation, atttup);

			heap_freetuple(atttup);
		}

		ReleaseSysCache(indextup);
	}

	freeList(indexoidlist);

	heap_close(attrelation, RowExclusiveLock);

	/*
	 * Update att name in any RI triggers associated with the relation.
	 */
	if (targetrelation->rd_rel->reltriggers > 0)
	{
		/* update tgargs column reference where att is primary key */
		update_ri_trigger_args(RelationGetRelid(targetrelation),
							   oldattname, newattname,
							   false, false);
		/* update tgargs column reference where att is foreign key */
		update_ri_trigger_args(RelationGetRelid(targetrelation),
							   oldattname, newattname,
							   true, false);
	}

	relation_close(targetrelation, NoLock);		/* close rel but keep
												 * lock! */
}

/*
 *		renamerel		- change the name of a relation
 *
 *		XXX - When renaming sequences, we don't bother to modify the
 *			  sequence name that is stored within the sequence itself
 *			  (this would cause problems with MVCC). In the future,
 *			  the sequence name should probably be removed from the
 *			  sequence, AFAIK there's no need for it to be there.
 */
void
renamerel(Oid myrelid, const char *newrelname)
{
	Relation	targetrelation;
	Relation	relrelation;	/* for RELATION relation */
	HeapTuple	reltup;
	Oid			namespaceId;
	char	   *oldrelname;
	char		relkind;
	bool		relhastriggers;

	/*
	 * Grab an exclusive lock on the target table or index, which we will
	 * NOT release until end of transaction.
	 */
	targetrelation = relation_open(myrelid, AccessExclusiveLock);

	oldrelname = pstrdup(RelationGetRelationName(targetrelation));
	namespaceId = RelationGetNamespace(targetrelation);

	if (!allowSystemTableMods && IsSystemRelation(targetrelation))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("permission denied: \"%s\" is a system catalog",
						RelationGetRelationName(targetrelation))));

	relkind = targetrelation->rd_rel->relkind;
	relhastriggers = (targetrelation->rd_rel->reltriggers > 0);

	/*
	 * Find relation's pg_class tuple, and make sure newrelname isn't in
	 * use.
	 */
	relrelation = heap_openr(RelationRelationName, RowExclusiveLock);

	reltup = SearchSysCacheCopy(RELOID,
								PointerGetDatum(myrelid),
								0, 0, 0);
	if (!HeapTupleIsValid(reltup))		/* shouldn't happen */
		elog(ERROR, "cache lookup failed for relation %u", myrelid);

	if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_TABLE),
				 errmsg("relation \"%s\" already exists",
						newrelname)));

	/*
	 * Update pg_class tuple with new relname.	(Scribbling on reltup is
	 * OK because it's a copy...)
	 */
	namestrcpy(&(((Form_pg_class) GETSTRUCT(reltup))->relname), newrelname);

	simple_heap_update(relrelation, &reltup->t_self, reltup);

	/* keep the system catalog indexes current */
	CatalogUpdateIndexes(relrelation, reltup);

	heap_freetuple(reltup);
	heap_close(relrelation, RowExclusiveLock);

	/*
	 * Also rename the associated type, if any.
	 */
	if (relkind != RELKIND_INDEX)
		TypeRename(oldrelname, namespaceId, newrelname);

	/*
	 * Update rel name in any RI triggers associated with the relation.
	 */
	if (relhastriggers)
	{
		/* update tgargs where relname is primary key */
		update_ri_trigger_args(myrelid,
							   oldrelname,
							   newrelname,
							   false, true);
		/* update tgargs where relname is foreign key */
		update_ri_trigger_args(myrelid,
							   oldrelname,
							   newrelname,
							   true, true);
	}

	/*
	 * Close rel, but keep exclusive lock!
	 */
	relation_close(targetrelation, NoLock);
}


/*
 * Given a trigger function OID, determine whether it is an RI trigger,
 * and if so whether it is attached to PK or FK relation.
 *
 * XXX this probably doesn't belong here; should be exported by
 * ri_triggers.c
 */
static int
ri_trigger_type(Oid tgfoid)
{
	switch (tgfoid)
	{
		case F_RI_FKEY_CASCADE_DEL:
		case F_RI_FKEY_CASCADE_UPD:
		case F_RI_FKEY_RESTRICT_DEL:
		case F_RI_FKEY_RESTRICT_UPD:
		case F_RI_FKEY_SETNULL_DEL:
		case F_RI_FKEY_SETNULL_UPD:
		case F_RI_FKEY_SETDEFAULT_DEL:
		case F_RI_FKEY_SETDEFAULT_UPD:
		case F_RI_FKEY_NOACTION_DEL:
		case F_RI_FKEY_NOACTION_UPD:
			return RI_TRIGGER_PK;

		case F_RI_FKEY_CHECK_INS:
		case F_RI_FKEY_CHECK_UPD:
			return RI_TRIGGER_FK;
	}

	return RI_TRIGGER_NONE;
}

/*
 * Scan pg_trigger for RI triggers that are on the specified relation
 * (if fk_scan is false) or have it as the tgconstrrel (if fk_scan
 * is true).  Update RI trigger args fields matching oldname to contain
 * newname instead.  If update_relname is true, examine the relname
 * fields; otherwise examine the attname fields.
 */
static void
update_ri_trigger_args(Oid relid,
					   const char *oldname,
					   const char *newname,
					   bool fk_scan,
					   bool update_relname)
{
	Relation	tgrel;
	ScanKeyData skey[1];
	SysScanDesc trigscan;
	HeapTuple	tuple;
	Datum		values[Natts_pg_trigger];
	char		nulls[Natts_pg_trigger];
	char		replaces[Natts_pg_trigger];

	tgrel = heap_openr(TriggerRelationName, RowExclusiveLock);
	if (fk_scan)
	{
		ScanKeyEntryInitialize(&skey[0], 0x0,
							   Anum_pg_trigger_tgconstrrelid,
							   F_OIDEQ,
							   ObjectIdGetDatum(relid));
		trigscan = systable_beginscan(tgrel, TriggerConstrRelidIndex,
									  true, SnapshotNow,
									  1, skey);
	}
	else