tablecmds.c

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

	 * Automatically create the secondary relation for TOAST if it
	 * formerly had no such but now has toastable attributes.
	 */
	AlterTableCreateToastTable(myrelid, true);
}

/*
 * ALTER TABLE ALTER COLUMN DROP NOT NULL
 */
void
AlterTableAlterColumnDropNotNull(Oid myrelid, bool recurse,
								 const char *colName)
{
	Relation	rel;
	HeapTuple	tuple;
	AttrNumber	attnum;
	Relation	attr_rel;
	List	   *indexoidlist;
	List	   *indexoidscan;

	rel = heap_open(myrelid, AccessExclusiveLock);

	if (rel->rd_rel->relkind != RELKIND_RELATION)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("\"%s\" is not a table",
						RelationGetRelationName(rel))));

	/* Permissions checks */
	if (!pg_class_ownercheck(myrelid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   RelationGetRelationName(rel));

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

	/*
	 * Propagate to children if desired
	 */
	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;
			AlterTableAlterColumnDropNotNull(childrelid,
											 false, colName);
		}
	}

	/* now do the thing on this relation */

	/*
	 * get the number of the attribute
	 */
	attnum = get_attnum(myrelid, colName);
	if (attnum == InvalidAttrNumber)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_COLUMN),
			 errmsg("column \"%s\" of relation \"%s\" does not exist",
					colName, RelationGetRelationName(rel))));

	/* Prevent them from altering a system attribute */
	if (attnum < 0)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot alter system column \"%s\"",
						colName)));

	/*
	 * Check that the attribute is not in a primary key
	 */

	/* Loop over all indexes on the relation */
	indexoidlist = RelationGetIndexList(rel);

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

		indexTuple = SearchSysCache(INDEXRELID,
									ObjectIdGetDatum(indexoid),
									0, 0, 0);
		if (!HeapTupleIsValid(indexTuple))
			elog(ERROR, "cache lookup failed for index %u", indexoid);
		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);

		/* If the index is not a primary key, skip the check */
		if (indexStruct->indisprimary)
		{
			/*
			 * Loop over each attribute in the primary key and see if it
			 * matches the to-be-altered attribute
			 */
			for (i = 0; i < indexStruct->indnatts; i++)
			{
				if (indexStruct->indkey[i] == attnum)
					ereport(ERROR,
							(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
						   errmsg("column \"%s\" is in a primary key",
								  colName)));
			}
		}

		ReleaseSysCache(indexTuple);
	}

	freeList(indexoidlist);

	/*
	 * Okay, actually perform the catalog change
	 */
	attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);

	tuple = SearchSysCacheCopyAttName(myrelid, colName);
	if (!HeapTupleIsValid(tuple))		/* shouldn't happen */
		elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u",
			 colName, myrelid);

	((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;

	simple_heap_update(attr_rel, &tuple->t_self, tuple);

	/* keep the system catalog indexes current */
	CatalogUpdateIndexes(attr_rel, tuple);

	heap_close(attr_rel, RowExclusiveLock);

	heap_close(rel, NoLock);
}

/*
 * ALTER TABLE ALTER COLUMN SET NOT NULL
 */
void
AlterTableAlterColumnSetNotNull(Oid myrelid, bool recurse,
								const char *colName)
{
	Relation	rel;
	HeapTuple	tuple;
	AttrNumber	attnum;
	Relation	attr_rel;
	HeapScanDesc scan;
	TupleDesc	tupdesc;

	rel = heap_open(myrelid, AccessExclusiveLock);

	if (rel->rd_rel->relkind != RELKIND_RELATION)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("\"%s\" is not a table",
						RelationGetRelationName(rel))));

	/* Permissions checks */
	if (!pg_class_ownercheck(myrelid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   RelationGetRelationName(rel));

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

	/*
	 * Propagate to children if desired
	 */
	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;
			AlterTableAlterColumnSetNotNull(childrelid,
											false, colName);
		}
	}

	/* now do the thing on this relation */

	/*
	 * get the number of the attribute
	 */
	attnum = get_attnum(myrelid, colName);
	if (attnum == InvalidAttrNumber)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_COLUMN),
			 errmsg("column \"%s\" of relation \"%s\" does not exist",
					colName, RelationGetRelationName(rel))));

	/* Prevent them from altering a system attribute */
	if (attnum < 0)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot alter system column \"%s\"",
						colName)));

	/*
	 * Perform a scan to ensure that there are no NULL values already in
	 * the relation
	 */
	tupdesc = RelationGetDescr(rel);

	scan = heap_beginscan(rel, SnapshotNow, 0, NULL);

	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
	{
		Datum		d;
		bool		isnull;

		d = heap_getattr(tuple, attnum, tupdesc, &isnull);

		if (isnull)
			ereport(ERROR,
					(errcode(ERRCODE_NOT_NULL_VIOLATION),
					 errmsg("column \"%s\" contains null values",
							colName)));
	}

	heap_endscan(scan);

	/*
	 * Okay, actually perform the catalog change
	 */
	attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);

	tuple = SearchSysCacheCopyAttName(myrelid, colName);
	if (!HeapTupleIsValid(tuple))		/* shouldn't happen */
		elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u",
			 colName, myrelid);

	((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;

	simple_heap_update(attr_rel, &tuple->t_self, tuple);

	/* keep the system catalog indexes current */
	CatalogUpdateIndexes(attr_rel, tuple);

	heap_close(attr_rel, RowExclusiveLock);

	heap_close(rel, NoLock);
}

/*
 * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
 */
void
AlterTableAlterColumnDefault(Oid myrelid, bool recurse,
							 const char *colName,
							 Node *newDefault)
{
	Relation	rel;
	AttrNumber	attnum;

	rel = heap_open(myrelid, AccessExclusiveLock);

	/*
	 * We allow defaults on views so that INSERT into a view can have
	 * default-ish behavior.  This works because the rewriter substitutes
	 * default values into INSERTs before it expands rules.
	 */
	if (rel->rd_rel->relkind != RELKIND_RELATION &&
		rel->rd_rel->relkind != RELKIND_VIEW)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("\"%s\" is not a table or view",
						RelationGetRelationName(rel))));

	/* Permissions checks */
	if (!pg_class_ownercheck(myrelid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   RelationGetRelationName(rel));

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

	/*
	 * Propagate to children if desired
	 */
	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;
			AlterTableAlterColumnDefault(childrelid,
										 false, colName, newDefault);
		}
	}

	/* now do the thing on this relation */

	/*
	 * get the number of the attribute
	 */
	attnum = get_attnum(myrelid, colName);
	if (attnum == InvalidAttrNumber)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_COLUMN),
			 errmsg("column \"%s\" of relation \"%s\" does not exist",
					colName, RelationGetRelationName(rel))));

	/* Prevent them from altering a system attribute */
	if (attnum < 0)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot alter system column \"%s\"",
						colName)));

	/*
	 * Remove any old default for the column.  We use RESTRICT here for
	 * safety, but at present we do not expect anything to depend on the
	 * default.
	 */
	RemoveAttrDefault(myrelid, attnum, DROP_RESTRICT, false);

	if (newDefault)
	{
		/* SET DEFAULT */
		RawColumnDefault *rawEnt;

		rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
		rawEnt->attnum = attnum;
		rawEnt->raw_default = newDefault;

		/*
		 * This function is intended for CREATE TABLE, so it processes a
		 * _list_ of defaults, but we just do one.
		 */
		AddRelationRawConstraints(rel, makeList1(rawEnt), NIL);
	}

	heap_close(rel, NoLock);
}

/*
 * ALTER TABLE ALTER COLUMN SET STATISTICS / STORAGE
 */
void
AlterTableAlterColumnFlags(Oid myrelid, bool recurse,
						   const char *colName,
						   Node *flagValue, const char *flagType)
{
	Relation	rel;
	int			newtarget = 1;
	char		newstorage = 'p';
	Relation	attrelation;
	HeapTuple	tuple;
	Form_pg_attribute attrtuple;

	rel = heap_open(myrelid, AccessExclusiveLock);

	if (rel->rd_rel->relkind != RELKIND_RELATION)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("\"%s\" is not a table",
						RelationGetRelationName(rel))));

	/* Permissions checks */
	if (!pg_class_ownercheck(myrelid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   RelationGetRelationName(rel));

	/*
	 * we allow statistics case for system tables
	 */
	if (*flagType != 'S' && !allowSystemTableMods && IsSystemRelation(rel))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("permission denied: \"%s\" is a system catalog",
						RelationGetRelationName(rel))));

	/*
	 * Check the supplied parameters before anything else
	 */
	if (*flagType == 'S')
	{
		/* STATISTICS */
		Assert(IsA(flagValue, Integer));
		newtarget = intVal(flagValue);

		/*
		 * Limit target to a sane range
		 */
		if (newtarget < -1)
		{
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("statistics target %d is too low",
							newtarget)));
		}
		else if (newtarget > 1000)
		{
			newtarget = 1000;
			ereport(WARNING,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("lowering statistics target to %d",
							newtarget)));
		}
	}
	else if (*flagType == 'M')
	{
		/* STORAGE */
		char	   *storagemode;

		Assert(IsA(flagValue, String));
		storagemode = strVal(flagValue);

		if (strcasecmp(storagemode, "plain") == 0)
			newstorage = 'p';
		else if (strcasecmp(storagemode, "external") == 0)
			newstorage = 'e';
		else if (strcasecmp(storagemode, "extended") == 0)
			newstorage = 'x';
		else if (strcasecmp(storagemode, "main") == 0)
			newstorage = 'm';
		else
			er