PostgreSQL Locking Questions

There is no LOCK TABLE in the SQL standard, which instead uses SET TRANSACTION to specify concurrency levels on transactions. You should be able to use LOCK in transactions like this one

BEGIN WORK;
LOCK TABLE table_name IN ACCESS EXCLUSIVE MODE;
SELECT * FROM table_name WHERE id=10;
Update table_name SET field1=test WHERE id=10;
COMMIT WORK;

I actually tested this on my db.