How to track changes in many SQL Server databases from .NET application?

Question

Problem:

There are a lot of different databases, which is populated by many different applications directly (without any common application layer). Data can be accessed

Answer 1

You can use an open source realization of the SqlDependency class - SqlDependencyEx. It uses a database trigger and native Service Broker notification to receive events about the table changes. This is an usage example:

int changesReceived = 0;
using (SqlDependencyEx sqlDependency = new SqlDependencyEx(
          TEST_CONNECTION_STRING, TEST_DATABASE_NAME, TEST_TABLE_NAME)) 
{
    sqlDependency.TableChanged += (o, e) => changesReceived++;
    sqlDependency.Start();

    // Make table changes.
    MakeTableInsertDeleteChanges(changesCount);

    // Wait a little bit to receive all changes.
    Thread.Sleep(1000);
}

Assert.AreEqual(changesCount, changesReceived);

With SqlDependecyEx you are able to monitor just INSERT or DELETE, avoiding UPDATE. Hope this helps.