Subject Re: [firebird-support] INSERT or Update and conflict
Author Milan Babuskov
svanderclock wrote:
> so some time i get some violation of PRIMARY or UNIQUE KEY when 2
> client do an INSERT because at the same time these 2 clients do the
> same insert and unfortunatly one of them go in the violation of primary
> key.... I just want to know the best way to handle such situation ?

It depends on what it means from business logic point of view. If you
really want to disallow two records with that value, then just ignore
the second insert that failed (maybe write to some log somewhere). Just
check the SQL error code to make sure it failed because of duplicate
primary key.

If you want both to succeed and have two records, than obviously you
need to set some other field to be the primary key.

> now in the same kind, sometime i get 'Update Error - lock conflict on
> no wait transaction'. it's when 2 clients try to update the same row at
> the same time. here also how to handle such situation ? is it possible
> to force the update of the row by the second request instead of raising
> a lock conflict?

Yes. Catch the lock conflict and retry from your application code. Once
again, checking that it failed because of such error and not something
else is desirable.

Milan Babuskov