Reg: Oracle to mysql server connection

Hi experts,

I have to create db link from oracle db to gateway mysql server, how can i create the db link.

I have addedd the listener entry from Gateway server to tnsnames.ora file in oracle db server, ,and tnsping is working fine.

after this i need to create the dblink to connect from oracle to mysql server db, but i dont' have username and password to create db link.

Any suggestions.