Hello,

because of this bug we have big problems with our customer.

When can we get an update?!

Thanks!

Hello Paul,

We reviewed that once again + your setting in TADConnection and TADTable components.
The way it's configured now the application works as designed.
Your connection has the pessimistic (more) locking mode:
That will in turn mean that for ADTable2 on Edit method call the record will be locked and a transaction started.
On Cancel the transaction will be rolled back.
Your options in this case could be:
- wrapping all code into explicit StartTransaction / Commit calls:
- not using pessimistic locking for AnyConnection1
- not using pessimistic locking for ADTable2 (setting its UpdateOptions will override connection ones)

Please let us know if this helped.

hello,

first of all, we need pessimistic locking!

The example code was just to illustrate the problem.

We have many forms with tableobjects and our customer can switch between these forms. So he works in form1 and edit the table in this form. Now he changes to form2 (the table in form1 is still in editmode) and works there (Perhaps he writes 5 invoices ). Then he returns to form1 and cancel the table. The result is: The invoices are gone. That can't be!

To set a pessimistic lock a transaction must be started, then a lock will be placed. To cancel editing and release the lock, the transaction must be rolled back.

MySQL supports only single transaction per connection. So, it is impossible to manage two and more pessimistic locks in the same connection independently. This is not AnyDAC limitation, it is how MySQL is designed. For example, the same will be with Oracle or SQL Server. But with Firebird you may have few active transactions in the same connection.

Additional option to the previous post is to use a dedicated connection for each form. Then each form will be able to manage pessimistic lock independently from other active forms.

Thanks Dmitry,

for your answer.
Ok, i have to use a dedicated connection for each form...

You welcome.

But be carefull, because different connections may not see each other data changes, may lead to locking of each other, etc.