> I'm really new to Firebird (and pretty new to SQL development
> altogether). I'm having some problems with an app that I hope

someone can

> help with.
>
> I've got an app that is currently using superserver mode to talk to a
> Firebird database. The database is installed on the same PC the app

runs from.

>
> The app potentially adds several thousand records at once, and does it
> using threads. Each thread creates a new Query object to perform any
> queries or updates.
>
> Once the app is completed, It's extremely likely it will be released

using

> the embedded server. As a result, all the threads and queries are

using the

> same database connection (unless I'm wrong, I can only have one

connection

> with the embedded server?)

No you can not do this because the connection is NOT threadsafe.

An embedded server is able to support multiple connections providing
they are initiated by a single process. Each thread must have its own
connection object. Not sure about whether they can share a transaction
or not, but I doubt it.

This probably explains your AV below.

Adam

>
> The problem I'm having seems to be occurring if a thread is actively

adding

> records and I try and refresh the view in the app (main thread,

performing

> a select), I get either an access violation or
> the following SQL exception:
>
> Error Code: -901. "Unsuccessful execution caused by system error

that does

> not preclude successful execution of subsequent statements."
>
> I'm a bit confused. Should I be creating a new connection for each
> query? Won't that stop me using the embedded server? Apologies if

this is

> documented somewhere, I've read somewhere in the region of 800 pages of
> Firebird and Interbase documentation today and I've mildly fried my

brain.

>
> Developing using Firebird 1.5 and Delphi 7 with Zeoslib 6.5.1 in

case that

> helps explain anything.
>
> Cheers,
> Rik
>