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
selectpk.table_name, c.COLUMN_NAME
fromINFORMATION_SCHEMA.TABLE_CONSTRAINTS pk 
INNER JOININFORMATION_SCHEMA.KEY_COLUMN_USAGE c
ON c.TABLE_NAME = pk.TABLE_NAME
andc.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