How Can I Ensure a SQL Server Table Remains Locked Until a Stored Procedure Completes?

Ensuring Table Locking in SQL Server During Stored Procedure Execution

Scenario:

A stored procedure (Procedure A) needs exclusive access to table 'a' to perform updates. A report in SQL Server Reporting Services (SSRS) needs to display the data from 'a' only after Procedure A finishes, preventing inconsistencies.

Solution:

The most effective way to guarantee this is by using transactions and appropriate locking hints:

Code Example:

CREATE PROCEDURE ProcedureA AS
BEGIN
    BEGIN TRANSACTION;  -- Initiate a transaction

    SELECT ...
    FROM a WITH (XLOCK, HOLDLOCK); -- Exclusive lock (XLOCK) and hold the lock until the transaction ends (HOLDLOCK)
    WHERE ...;

    -- Perform operations not directly involving table 'a' here...

    -- Update table 'a' ...

    COMMIT TRANSACTION;  -- Commit the transaction, releasing the lock
END;

Explanation:

• BEGIN TRANSACTION;: Starts a transaction. All operations within the transaction are treated as a single unit of work.
• SELECT ... FROM a WITH (XLOCK, HOLDLOCK);: This SELECT statement, crucially, uses the XLOCK hint to acquire an exclusive lock on table 'a'. HOLDLOCK ensures the lock is held until the transaction completes, even across multiple statements. This prevents any other processes from reading or writing to 'a' during Procedure A's execution.
• -- Perform operations not directly involving table 'a' here...: Other operations can be performed here.
• -- Update table 'a' ...: The updates to table 'a' are performed within the transaction.
• COMMIT TRANSACTION;: The transaction is committed, making the changes permanent and releasing the exclusive lock on table 'a'. If an error occurs, ROLLBACK TRANSACTION; should be used to undo any changes and release the lock.

This approach ensures data integrity by preventing concurrent access to the table while the stored procedure is running. The SSRS report will then accurately reflect the updated data after the procedure completes.

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