How to get the “start_lsn” value in application code

Question

The database tracks all changes via the "Change Data Capture" mechanism. I need to add additional information about users who make these changes. The following users are not SQL Server users. Security authorization is performed via an outside mechanism.

I want to add a helper table with columns "start_lsn" and "userId" to associate a transaction with the authorized user. Is there any way to determine the "start_lsn" value, which corresponds to the current transaction executed in the application code?

Answer 1

At present, I have found the following solution:

1)

• Create one more table (for example, the "UserActivity"), which has the "ID" and "userId" columns;

• Use the "ID" column as the Primary Key;

• Enable the CDC option for this table.

2)

• Wrap all data modification operations with a transaction scope;

• Add a new data record into this table with the current "userId" during a particular transaction:

  • Begin Exclusive Transaction;

  • Perform "Data Manipulation";

  • Insert Information about "userId" into the "UserActivity" table.

Since the transaction is exclusive and all operations were made within a single transaction scope, the "last_lsn" ("start_lsn") value is the same.

After that, using the JOIN operator, merge data from the "UserActivity" table with Data Manipulation information.