Subject select with lock
Author L.M. Bemmelmans
FB 1.5 has a new feature select * from table with lock

Could someone explain to me how this works. it a kind of record locking (if your where clause collects only 1
record ) ?
2.does it lock all fields in the where clause or complete records long are records locked ? until post or until commit ? it an alternative for thoe old recordlocking ?