Understanding SQL Server THROW: Tips and Tricks for Developers

Hey there Dev! Are you having trouble understanding how to use SQL Server THROW in your development? Don’t worry, you’re not alone! In this article, we’ll dive deep into the concept and provide you with some tips and tricks to use SQL Server THROW efficiently. Let’s get started!

What is SQL Server THROW?

SQL Server THROW is an error handling feature that was introduced in SQL Server 2012. It allows developers to throw custom errors from their T-SQL code. This means that if there is an error in your code, you can provide a custom message along with the error number to help the end user understand what went wrong. This feature is particularly helpful in debugging and troubleshooting scenarios.

Let’s take a closer look at how to use SQL Server THROW.

The Syntax for SQL Server THROW

The syntax for SQL Server THROW is pretty straightforward. Here’s what it looks like:

Parameter	Description
error_number	The number that represents the error.
error_message	The custom message that is displayed with the error.
state	An optional parameter that specifies the state of the error.

Here’s an example of how to use SQL Server THROW:

BEGIN TRY-- Your T-SQL code goes hereEND TRYBEGIN CATCHTHROW 51000, 'An error occurred while executing the T-SQL code', 1;END CATCH;

In this example, if there is an error in the T-SQL code, the custom error message ‘An error occurred while executing the T-SQL code’ will be displayed along with the error number 51000.

When to Use SQL Server THROW

SQL Server THROW should be used in scenarios where you want to provide a custom error message to the end user. This is particularly useful in scenarios where the error message generated by SQL Server is not helpful or clear enough.

For example, let’s say you have a stored procedure that inserts data into a table. If there is a problem with the data and the insert fails, SQL Server will generate an error message. However, this message may not be helpful to the end user. With SQL Server THROW, you can provide a custom message that explains what went wrong and how to fix it.

Best Practices for Using SQL Server THROW

Use Descriptive Error Messages

When using SQL Server THROW, it’s important to use descriptive error messages that are helpful to the end user. This means avoiding generic error messages like ‘An error occurred’ and instead providing specific details about what went wrong and how to fix it.

Include Error Numbers

Including error numbers in your custom error messages can be helpful in debugging and troubleshooting scenarios. This allows developers to quickly identify the source of the error and take appropriate action.

Be Careful with the State Parameter

The state parameter in SQL Server THROW is an optional parameter that specifies the state of the error. This can be helpful in tracing the error back to its source, but it should be used with caution. If you set the state parameter to a value that is too high, it can cause confusion and make it more difficult to troubleshoot the error.

FAQs

What is the Difference Between RAISERROR and THROW?

RAISERROR is a legacy error handling feature that has been around since SQL Server 6.5. It is still supported in SQL Server 2019, but it is recommended that developers use THROW instead. The main difference between RAISERROR and THROW is that THROW provides a more streamlined syntax and is easier to use.

Can I Use SQL Server THROW in SQL Server 2008?

No, SQL Server THROW was introduced in SQL Server 2012. If you’re using SQL Server 2008, you’ll need to use RAISERROR instead.

What Happens if I Don’t Use Error Handling in my T-SQL Code?

If you don’t use error handling in your T-SQL code, SQL Server will generate an error message whenever an error occurs. This message may not be helpful to the end user and can make it more difficult to troubleshoot the error. Using error handling features like SQL Server THROW can help provide more helpful and detailed error messages.

Can I Use SQL Server THROW in Stored Procedures?

Yes, SQL Server THROW can be used in stored procedures, functions, and triggers.

What Should I Do If I’m Having Trouble Debugging an Error?

If you’re having trouble debugging an error, there are several things you can do. First, make sure you’re using error handling features like SQL Server THROW. This can help provide more helpful error messages that can aid in troubleshooting. Additionally, consider using tools like SQL Server Profiler and the SQL Server Management Studio debugger to help identify the source of the error.

Conclusion

SQL Server THROW is a powerful error handling feature that can help developers provide more helpful and informative error messages to end users. By following best practices like using descriptive error messages and including error numbers, developers can take full advantage of this feature to make their T-SQL code more efficient and effective.