Transaction in additional service

Data Abstract
1

Hi,

I have added a new service (e.g. BatchService) to my existing DA Server.
Operations in this service should process data using a LinqLocalDataAdapter .
How can I manage transactions in this service?

2

Hello

What exactly you mean by ‘managing transactions’?

3

In the usual data service you would do something like this:

Connection.BeginTransaction();
…
Connection.CommitTransaction();

In a service that is not derived form DataAbstractService, there is no Connection object available. Even if it is derived from DataAbstractService it does have a connection, but the database access is running in a transaction of the DataService specified in LinqLocalDataAdapter’s ServiceName property.

Is there a way to have a simple service (not derived form DataAbstractService) with a LinqLocalDataAdapter and get acceess to the Connection of the LinqLocalDataAdapter’s DataService?

4

Hello

It is possible to use the local data adapter using a pre-instantiated service instance, so it is possible to explicitly control the transaction scope. The code could look like

    
var service = new DataService();
try
{
    service.Activate(this.SessionID);
    service.Connection.BeginTransaction();
    var adapter = new LinqLocalDataAdapter(service);
    
    // do the work
    
    service.Connection.CommitTransaction();
}
finally
{
    service.Deactivate(this.SessionID);
    service = null;
}
5

Hello Anton,

thanks for your reply.

What I did not really like with it is to always create a new instance of the DataService.
So I started some more research in the DA source code and found the IDataAbstractLocalServiceAccess interface. When setting the LinqLocalDataAdapter’s ServiceName property I would expect that the ServiceInstance property already returns an instance of the DataService. So I tried the following solution, which seems to be working correctly.

        var Service = (DataAbstractService)linqLocalDataAdapter.ServiceInstance;
        Service.Connection.BeginTransaction();
        try
        {
            .. so some data processing
            Service.Connection.CommitTransaction();
        }
        catch (Exception)
        {
            Service.Connection.RollbackTransaction();
            throw;
        }

What is your opinion about this? Can it be done this way?

Thanks,
Georg

6

Hello

Yes this approach will work as well. In this case service instance is instantiated and activated during 1st access to the .ServiceInstance property.