[sqlite] a question about muticonnection

[hongdong]

I just have a base question:
assume user A and user B now both connection to a same database and both of
them want to update a  same record,but only one is allowed
in  this condition:
A begin to browse the data in a client application,and load rowid into GUI
and keep it in memory.
B update the record which A want to update
A now used the id stored in memory to update the same record
now it's wrong.
anyone can give me advice how to avoid this and keep the operation is
effient
thanks!