As a SQL Server database administrator (DBA), it is crucial to have a solid understanding of error handling in SQL Server. In this article, we will explore the concept of error handling and discuss some best practices for handling errors in SQL Server.
One of the new features introduced in SQL Server 2005 is the error handler. This error handler allows you to handle errors in a more efficient and organized manner. It is important to note that error handling is not limited to just the SQL Server itself, but can also be implemented in stored procedures.
When working with nested procedures, it is common to have one stored procedure act as a wrapper for one or multiple nested procedures. However, it is important to note that some errors with nested procedure calls are handled in a strange way. This can lead to confusion and difficulties in debugging.
To address this issue, it is recommended to create an error log table to store error and system data. This table will help you track and analyze errors that occur during the execution of stored procedures. The error log table should include columns such as error log ID, error log program name, error log error number, error log error description, and more.
Once the error log table is created, you can create a standard stored procedure that will load error-tracked information into the table. This stored procedure takes information provided by the code and stores it in the error log table. It also has the ability to store the set of parameters to the stored procedure where the error has occurred. This can be extremely helpful in debugging stored procedures and identifying specific errors that occur with specific input parameters.
It is important to note that SQL Server provides the “RAISERROR” command, which allows you to raise your own errors. This command returns an error code of your choice, along with a standard or custom level and message. This can be useful when you encounter a problem and want to raise a specific error code.
When working with transactional statements, it is important to handle errors properly to maintain data integrity. In some cases, errors can occur within a transaction and leave it in an uncommittable state. This can lead to issues with data consistency and integrity.
To avoid such situations, it is recommended to add specific code to non-transactional stored procedures that checks for errors and rolls back any open transactions. This ensures that the non-transactional procedure acts as a wrapper for the transactional procedure(s) and handles any open transactions appropriately.
It is important to note that these error handling techniques may not work properly if your application code is already handling transactions. However, for most modern applications, these techniques should be sufficient to handle errors effectively.
In conclusion, error handling is a critical aspect of SQL Server administration. By implementing proper error handling techniques, you can ensure data integrity, simplify debugging, and improve the overall performance and reliability of your SQL Server environment.