SQL Server: lock table during entire stored procedure

Question

I have a streaming ingestion into my staging table. Every 5 minutes I execute a stored procedure to insert/update all the data from this staging table into my final table.

Process of the stored procedure:

BEGIN
 - UPDATE RECORDS IN FINAL TABLE FROM STAGING TABLE
 - INSERT RECORDS IN FINAL TABLE FROM STAGING TABLE
 - TRUNCATE STAGING TABLE
HERE I WANT TO RELEASE THE LOCK
END

Any idea how I can explicitely say that I want to lock the staging table for inserts until I have truncated it?

Answer 1

You can execute these scripts in transactions block like this;

BEGIN
 BEGIN TRANSACTION
 - UPDATE RECORDS IN FINAL TABLE FROM STAGING TABLE
 - INSERT RECORDS IN FINAL TABLE FROM STAGING TABLE
 - TRUNCATE STAGING TABLE
 COMMIT TRANSACTION
HERE I WANT TO RELEASE THE LOCK
END

Another transactions will wait to finish your transaction block. And you should create try/catch block to handle error. If the script encouraged with error, you should ROLLBACK TRANSACTION in catch block. Because if a transaction is being started, it must be finished as COMMIT or ROLLBACK. You don't want that transaction is being hung.