SA0030 : Output parameter never assigned

The unused output parameters do not negatively impact performance directly, but they add clutter, making it harder to maintain and understand the code, which may lead to errors over time.

For example:

1-- Example of a stored procedure with an unused output parameter
2CREATE PROCEDURE GetEmployeeData
3    @EmployeeID INT,
4    @EmployeeName NVARCHAR(100) OUTPUT
5AS
6BEGIN
7    SELECT * FROM Employees WHERE EmployeeID = @EmployeeID;
8    -- @EmployeeName is not used
9END;

In this example, @EmployeeName is declared as an output parameter but never utilized within the procedure. This can mislead developers into thinking it serves a purpose, complicating debugging and maintenance tasks.

• Increases the risk of misunderstanding the procedure’s function, potentially causing integration or application logic errors.

• Leads to bloated codebases, making modifications and optimizations more challenging over time.

This section provides a step-by-step guide to removing unused output parameters from stored procedures and functions to simplify code and reduce maintenance complexity.

Follow these steps to address the issue:

1. Identify the stored procedure or function containing the unused output parameter by looking through the code or using tools such as SSMS to search for declarations of procedures with output parameters.

2. Examine the logic inside the procedure to confirm that the output parameter is not utilized. In cases where the parameter is declared but not referenced in the procedure body, it is considered unused.

3. Remove the declaration of the unused output parameter from the procedure’s signature. Update the procedure’s definition to eliminate any reference to the unused output parameter.

4. Consider updating any application code or database logic that calls the procedure to ensure there are no references to the removed output parameter.

5. Test the modified stored procedure to confirm that it operates correctly without the unused parameter and that the calling applications or scripts still function as expected.

For example:

1-- Example of fixed query without the unused output parameter
2CREATE PROCEDURE GetEmployeeData
3    @EmployeeID INT
4AS
5BEGIN
6    SELECT * FROM Employees WHERE EmployeeID = @EmployeeID;
7END;

The rule has a Batch scope and is applied only on the SQL script.

Rule has no parameters.

The rule does not need Analysis Context or SQL Connection.

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