Find possible missing foreign key relationships

/* First create a table function that  
  returns the primary key tables and columns */

If Exists (Select name from sysobjects where name = 'tblfn_PrimaryKeys')
	Drop Function tblfn_PrimaryKeys
GO

CREATE Function dbo.tblfn_PrimaryKeys()
RETURNS @Values table (TableName varchar(128), ColumnName varchar(128))
AS

/* Retrieves the table name and primary key columns for each table. */


BEGIN
Insert Into @Values
select	pk.table_name, c.COLUMN_NAME
	from	INFORMATION_SCHEMA.TABLE_CONSTRAINTS pk 
		INNER JOIN	INFORMATION_SCHEMA.KEY_COLUMN_USAGE c
		ON c.TABLE_NAME = pk.TABLE_NAME
		and	c.CONSTRAINT_NAME = pk.CONSTRAINT_NAME
	where 	CONSTRAINT_TYPE = 'PRIMARY KEY'
ORDER BY pk.table_name, c.column_name

RETURN

END
GO

/* Next create a table function that  
  returns the foreign key names, tables, and columns */

If Exists (Select name from sysobjects where name = 'tblfn_ForeignKeys')
	Drop Function tblfn_ForeignKeys
GO


CREATE Function dbo.tblfn_ForeignKeys()
Returns @ForeignKey table (ForeignKeyName varchar(128), PrimaryTable varchar(128), PrimaryColumn varchar(128),
	ForeignTable varchar(128),ForeignColumn varchar(128))

AS

/* Returns all foreign keys with the primary and foreign tables and column information. */
BEGIN
Insert Into @ForeignKey
Select sfko.name AS ForeignKeyName, sro.name AS PrimaryTable,  
	src.name AS PrimaryColumn, so.name AS ForeignTable, sc.name AS ForeignColumn
From sysforeignkeys sfk left outer join sysobjects so on sfk.fkeyid = so.id
	LEFT OUTER JOIN sysobjects sro on sfk.rkeyid = sro.id
	LEFT OUTER JOIN syscolumns src on sro.id = src.id and
	src.colid = sfk.rkey 
	LEFT OUTER JOIN syscolumns sc on so.id = sc.id and
	sc.colid = sfk.fkey 
	LEFT OUTER JOIN sysobjects sfko on sfk.constid = sfko.id
ORDER BY sro.name, so.name


Return 
END

GO
/* Finally, write the query to view all possible missing foreign keys */

Select T.Table_Name AS TableName, Column_Name AS ColumnName
	From INFORMATION_SCHEMA.Columns C LEFT OUTER JOIN 
		INFORMATION_SCHEMA.Tables T ON C.Table_Name = T.Table_Name
	WHERE T.table_type = 'Base table' and T.table_schema = 'dbo'  
	and T.Table_Name + Column_Name not in (
		Select ForeignTable + ForeignColumn
		From dbo.tblfn_ForeignKeys())
	 and T.Table_Name + Column_Name not in (
		Select TableName + ColumnName
		From dbo.tblfn_PrimaryKeys())
	 AND Column_Name in (
		Select ColumnName
		From dbo.tblfn_PrimaryKeys()) 
	ORDER BY T.Table_Name, Column_Name