added compare function to the more basic expression objects adding priamry_key/foreign_keys to selects, alias etc to increase their useability for relating them to tables improved _get_col_by_original to double-check the column it finds
added compare function to the more basic expression objects
adding priamry_key/foreign_keys to selects, alias etc to increase their useability for relating them to tables
improved _get_col_by_original to double-check the column it finds


git-svn-id: 655ff90ec95d1eeadb1ee4bb9db742a3c015d499@783 8cd8332f-0806-0410-a4b6-96f4b9520244

obeattie/sqlalchemy,obeattie/sqlalchemy,obeattie/sqlalchemy