Hello Helen,

thank you for your hints.

>

You have missing or wrong KeyLinks in your dataset object (TIB_Query, etc.)
<
I am using the query editor (dbl click on the query component) to generate the Edit-/Insert-/Update - SQL and I noticed that "generate for table" made a :

DELETE FROM <my table>
WHERE
RDB$DB_KEY = :DB_KEY

When I replace the

RDB$DB_KEY = :DB_KEY

with

PS_ID = :PS_ID

which is a UNIQUE ASCENDING INDEX on this table then every thing works fine.
What is the background of RDB$DB_KEY here?

>>Where do I have to put my try/Except to catch this exception?
>
>This isn't the kind of error that you could catch and throw back to the
>user - it's a programmer error.

You are definitely right her, but the reason I asked this question is:
I have a similar problem on two other tables. One holds current process data and the other is a process data archive. When a dataset gets "done" it is copied to the archive.
I have a KeySource-Lookoup relation on the process data using a IB_LookupCombo dropped on the grid.
If the user now selects the field to modify the lookup combo comes up giving him choice from a other table. If now the corresponding dataset gets copied to the archive before the user made his choice I get the Exception that "the datarow is not found to be updated". Now I could use the catch exception here and by code update the right dataset in the archieve.

So I still would like to know : Where do I have to put my try/Except to catch this exception?

Regards
Rainer