plpgsql

I 've a question about begin...end in plpgsql
does
sql stmts in
begin
....
end;
will go one transaction?

i.e.
begin...end have same meaning as sql stmts BEGIN...COMMIT??
if failed, transaction abort?
if select..for update is used then
another update stmt will wait on the same rows??

if begin...end in plpgsql connot have same functionality as
sql, how can I ensure my sql stmts go one transaction??

thanks.

Jie LIANG

St. Bernard Software

10350 Science Center Drive
Suite 100, San Diego, CA 92121
Office:(858)320-4873

jliang(at)ipinc(dot)com
www.stbernard.com
www.ipinc.com