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SQL Server 2008, UniDac-components.
I have to deliver a unique value (as a document-number with a specific format). So my idea is to lock a record (or the whole table), to read then last value, to modify it and to unlock the record / table. I tried it with
try
Connection.StartTransaction
Table.Open
Table.Lock
do by job
Table.Unlock
Table.Close
except
Showmessage('Sorry, table is locked ...');
end;

To test it I made two buttons, two tables and the code above in the OnClick-Event for each table. But there is never an excption fired. How to do it? Thanks for your help, Peter

Hello,

This error message occurs only in case of an attempt to perform simultaneous access to a locked table.
This error message occurs only in case you do not complete an already started transaction, before an attempt to access the table.

And how can I solve my task? Exclusive acces on a record or on a whole table?
Thanks Peter

hello,

If you don't need to change all records in the table, it is irrational to lock the whole table, it is sufficient to lock only the record that requires changing.

Thanks, but I don't know how to do it. Please give an example, Peter

hello,

To lock the record you are editing, set the LockMode property to lmPessimistic, in this case calling the Edit method will call the following command:
which will lock the current record

Thanks for your help, that works for me, Peter

Hello,

Glad to see that the problem was solved. If you have any other questions, feel free to contact us.