Last month's article demonstrated how the Retrieve Command Definition (QCDRCMDD) API could be used to access the list of SYSVAL special values associated with the DSPSYSVAL command, thereby removing the need to know in advance what system values are valid for the system the program is running on. The sample program then loaded these special value names into the array SysVals. This month, we'll look at how the Retrieve System Values (QWCRSVAL) API can be used to access the values associated with each system value name found in SysVals. For demonstration purposes, we'll display the various system values using a subfile.
Use the WITH keyword to make your SQL statements easier to code and maintain.
Written by Sam Lennon
Common table expressions (CTEs) allow you to break down complex SQL logic into smaller pieces. This makes development and testing easier, and when you come back to the code next year you'll understand it more quickly. That can't be bad, and a CTE is not hard to use. In this article, I'll provide working examples of CTEs that demonstrate their ease of use and the clarity they can provide.