Oracle: what is the “instantclient” connection string format?

Question

and how does it differ from the regular connection string?

Answer 1

Connecting with the instant client is no different than with the full stack client - all connect string formats are the same. If you installed the instant client in a non-standard location on the filesystem or are having problems connecting to the database listener, be sure that your TNS_ADMIN environment points to the directory that contains your tnsnames.ora and sqlnet.ora files,