Recently, during a modernization project, I have been making use of the Allow Repeated Change (ALWREPCHG) option with before triggers. ALWREPCHG allows a before trigger to make changes to the record being inserted or updated, and that lets you do some really powerful database magic!

The Scenario

A table contains a date that is stored in a packed numeric column. The requirement is to change the data type of the column to a proper date data type. This change will require coding changes to at least 20 programs.

The “big bang” approach of changing, testing and implementing the 20-plus programs

Sometimes an SQL query should return one row, yet it returns more than one. The problem turns out to be multiple matching rows in a secondary table. Is there a way to easily isolate the secondary table that causes more than one match?

–J

Yes, there is an easy way. But first, let me set up the problem for the edification of other readers.

Sometimes we execute an SQL query with the expectation that the result set will contain only one row (record), and we are surprised to get back two or more rows instead. At least one table (physical

Many IBM i shops run enterprise software originally created more than 10 years ago. While this allows you to run older applications on newer hardware, older apps can also cause issues with files that are no longer suitable for today’s processing. This week, let’s look at one older file parameter that if not changed, can stop application processing dead in its tracks: The 4 GB Access Path Size Time Bomb.

Time Bomb, What Time Bomb?

The time bomb I’m referring to is the Access path size (ACCPTHSIZ) parameter in some application files. In older versions of the OS/400 operating system