Need help for @table_qualifier

Hello Team,

Connection from Oracle to MS SQL working fine. But when passing below query
like

sp_columns
@table_name='slcustm_sap',@table_owner='test_owner',@table_qualifier='test_qualifier',@ODBCVer=3


but what is seen by mssql as

sp_columns @table_name='slcustm_sap',@table_owner='test_owner',@ODBCVer=3
with no table_qualifier

query I have is from where Oracle picks up table_qualifier details

1. odbc.ini 2. init*.ora for DG4ODBC 3. dblink  or any other place ?

Thanks
Raj