Triggers in SQL Server are powerful tools that allow you to automate actions when certain events occur in your database. However, there may be situations where you want to disable triggers for specific sessions, such as during bulk inserts or data loading operations. In this article, we will explore various ways to disable triggers in SQL Server for specific sessions.

Understanding “NOT FOR REPLICATION”

Before we dive into the methods of disabling triggers, let’s first understand the concept of “NOT FOR REPLICATION” in SQL Server. When creating triggers, you have the option to specify “NOT FOR REPLICATION”. This indicates that the triggers should not be fired when replication agents perform data modifications on the table. This hint can also be used for other database objects like foreign keys, identity columns, and check constraints.

For example, if you have triggers on a table that are set as “NOT FOR REPLICATION”, they will be fired when a normal user inserts, updates, or deletes data. However, these triggers will not be fired when replication agents perform the same data modifications.

Disabling Triggers for Specific Sessions

Now let’s explore the methods to disable triggers for specific sessions in SQL Server.

Method 1: Using Replication Agent

One way to disable triggers for a specific session is to log in as a replication agent. By logging in as a replication agent, the triggers that are set as “NOT FOR REPLICATION” will not be fired for that session. This can be useful when you want to load data into tables without triggering the associated actions defined in the triggers.

Here’s an example of how to log in as a replication agent and insert data into a table without firing the triggers:

-- Log in as replication agent
-- Execute INSERT statements without triggering the associated triggers

Method 2: Using CONTEXT_INFO()

Another method to disable triggers for a specific session is by using the CONTEXT_INFO() function in the trigger code. CONTEXT_INFO() allows you to store information specific to a session, which can be used to conditionally execute the trigger code.

Here’s an example of how to use CONTEXT_INFO() to disable triggers:

CREATE TRIGGER TR_INSEMPDETAILS ON Emp FOR INSERT AS
BEGIN
    SET NOCOUNT ON
    
    DECLARE @CONT_INFO VARBINARY(128)
    SELECT @CONT_INFO = CONTEXT_INFO()

    IF @CONT_INFO = 0x1256698456
        RETURN

    -- Trigger logic here
END

In this example, the trigger code will only be executed if the value stored in CONTEXT_INFO() matches the specified value. By setting the CONTEXT_INFO() value to a specific value before inserting data into the table, you can effectively disable the trigger for that session.

Method 3: Using BCP Utility or BULK INSERT

If you are loading data from a file (e.g., .txt or .csv) into a table, you can use the BCP utility or BULK INSERT options to disable triggers. By default, these methods do not fire triggers during the data loading process. However, you can force trigger execution by specifying the “FIRE_TRIGGERS” option.

Here’s an example of how to use the BCP utility with the “FIRE_TRIGGERS” option:

BCP [database].dbo.table in datafile.txt -T -c -S"servername" -Uusername -Ppassword -h "FIRE_TRIGGERS"

And here’s an example of how to use BULK INSERT with the “FIRE_TRIGGERS” option:

BULK INSERT table FROM 'datafile.txt' WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\n', FIRE_TRIGGERS)

By specifying the “FIRE_TRIGGERS” option, you can enable trigger execution during the data loading process.

Conclusion

Disabling triggers in SQL Server for specific sessions can be useful in scenarios where you want to perform bulk inserts or data loading operations without triggering the associated actions defined in the triggers. By understanding the “NOT FOR REPLICATION” concept and utilizing methods like logging in as a replication agent, using CONTEXT_INFO(), or using the BCP utility/BULK INSERT options, you can effectively disable triggers for specific sessions in SQL Server.