DB2 Stored Procedure Debugging Techniques
By Tom Nonmacher
Debugging stored procedures in IBM's DB2 is an art that requires a certain level of expertise. DB2 11.1, for instance, provides a rich set of tools and technologies to simplify the debugging process. Using the right techniques, you can identify and address issues in your stored procedures swiftly and efficiently.
The first step in debugging is to use the SET statement to turn on the debugging mode. The SQL command for this is as follows:
SET CURRENT DEBUG MODE ON
This instructs DB2 to compile the stored procedure with debugging information. However, remember to turn off debugging mode once you have finished to prevent unnecessary overhead.
You can also use the Debugger for DB2 for z/OS to debug stored procedures. This powerful tool allows you to set breakpoints, step through code, and examine variables and SQLCA information.
Another effective debugging technique involves the use of the GET DIAGNOSTICS statement. This statement retrieves detailed information about the previous SQL statement. To illustrate, consider the following SQL code example:
-- After executing a SQL statement
GET DIAGNOSTICS :sqlstate = RETURNED_SQLSTATE,:sqlcode = DB2_SQLCODE,
:message_text = MESSAGE_TEXT;
In this example, the GET DIAGNOSTICS statement retrieves the SQLSTATE, SQLCODE, and MESSAGE_TEXT values and stores them in the respective variables.
Although our focus is on DB2, it's worth noting that other SQL platforms such as SQL Server 2016, SQL Server 2017, MySQL 5.7, and Azure SQL also offer robust debugging tools. SQL Server, for example, includes the Transact-SQL Debugger that lets you pause the execution of Transact-SQL statements, stored procedures, and functions.
MySQL 5.7, on the other hand, does not have a built-in debugger. However, you can use third-party tools like MySQL Workbench or Toad for MySQL to debug stored procedures. Azure SQL Database, Microsoft's fully managed cloud database service, supports stored procedure debugging through the Visual Studio's SQL Server Object Explorer.
In conclusion, debugging stored procedures in DB2 or any other SQL platform need not be a daunting task. With the right tools and techniques, you can identify and fix issues quickly and efficiently. Be sure to leverage the debugging capabilities of your SQL platform to ensure the reliability and performance of your stored procedures.