Hi everyone - hope you all had a good break.
Looks like summer has finally arrived (now that everyone's back at work)!
Anyway...
I'm using Firebird (and transactions) for the
first time. I'm connecting to a remote database via the Firebird Server with
no problems, but I have a question about transactions:
When I insert a new record, I use a trigger and a
generator to generate a new unique ID for the new record - I also query the
generator to see what the new value is that was returned by the trigger. The
code snippet is as follows:
orderTransaction.Active := True;
with
orderQuery do //insert the
record
begin
ExecQuery;
with
IBCurrentGeneratorValueQuery do //
this query fetches the current value of the
generator
try
Transaction
:= orderTransaction; // share the same
transaction as the
order
Open;
result:=FieldByName('newID').asInteger; // get
the generator value
except
result:=-1;
end;
orderTransaction.Commit;
end;
The question is, if multiple clients access the
database server at the same time, will IBCurrentGeneratorValueQuery still return the correct value, or
if another concurrent transaction on another thread increments the generator,
will this query return the wrong value?
When I was using MySQL (with PHP) I could use
mysql_insert_id() to query the new key value. I guess that if I
could get hold of the newly inserted row I could just get the field value, but
the same concurrency issue applies and I'm not sure how to get the record I
just inserted.
Cheers,
Phil.
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