Newbie postgres/JDBC question.

Hi all!

I have a question that pertains to the update of records in a postgres
database using JDBC. I extract a record from the database for update and,
and after modification to the record, I place these changes into postgres.
It does not look, via the documentation on JDBC, as if I have prevented
someone from making changes at the same time. Is there a command that I
must first perform to lock a record that is being updated? If a record is
locked when another user wants access, what type of error information can be
acquired to pass on to the user?

Sincerely,

David Langschied
Langschied Consulting Services
25644 Mackinac
Roseville, MI 48066

Phone: (586)777-7542
Cell: (248)789-8493
e-mail: dlangschied(at)ameritech(dot)net