🚀 go-pugleaf

Kovalenko Dmitry wrote:
>> Also it appears that there is no way to support overlapped
>> transactions as opposed to either single transactions or nested
>> transactions in ADO/OLEDB. Some databases, such as Interbase,
>> support overlapped transactions and not nested transactions.
>
> Yes, InterBase connection can have multiple overlapped transactions
> http://www.ibprovider.com/eng/examples/example_09_02.html
>
> Once again:
>  - Support of overlapped transactions - "Active Sessions" >1 (or ==0).
>  - Property with information about support nested transaction not
> exists.

Why does Active Sesssions > 1 or == 0 indicate support for overlapped
transactions ?

>
>> If I call
>> TADOConnection::BeginTrans() using Interbase and a transaction
>> already exists in the connection, does BeginTrans() fail and throw
>> an exception or does it succeed and return a value of 1 indicating a
>> top-level transaction ?
>
> In this case, InterBase OLEDB provider must be throw exception with
> error code ....

If InterBase OLEDB provider supported overlapped transactions, the starting
a second transaction from a session should not fail. The problem with
ADO/OLEDB and overlapped transactions is that there is no way to specify
which transaction to commit and/or rollback if two or more overlapped
transactions are running at the same time.

>
> Apropos, current status of transaction (session object) you can
> receive througn ITransaction::GetTransactionStatus

Good information to know. However I am not sure how to go from ADO objects
to the underlying OLEDB interfaces. In this example I would want to go from
my ADO Connection object to its underlying ITransaction interface. How would
I do that ?