IBM i is more than an AS400

I frequently get messages asking why does IBM call it IBM i when it is just an AS/400, or even System/38, by another name. Talking to other authors and IBM-ers I find that I am not alone to receive communications like this.

Steve Will, chief architect for IBM i, has felt compelled to dispel this fallacy. Earlier this month he made an online presentation, sponsored by HelpSystems, explaining how IBM i differs and is a lot more than AS/400. The video can be watched on the sponsor's website here.

The video lasts just over an hour, and, in my opinion, is worth watching to learn the evolution of the operating system to become the thoroughly modern IBM i.

Position cursor into field on screens

The germ for this post's subject came from a two part question I was asked:

1. How can I know which field the cursor is in when Enter is pressed?
2. How can I position a cursor on some field without using indicators? No indicators are available in that very old screen.

Fortunately there are ways to do this by adding a few keywords and fields to the display file's DDS. In these examples I am going to use one display file with three screens, each showing a way to do what has been asked, and the RPG code needed too (and I am going to cheat on the second part).

DB2 name change

Last week at OCEAN User Group's Technical Conference I attended a couple of sessions by Scott Forstie, IBM's Business Architect for DB2 for i. I noticed in his presentation he had used "Db2" rather than "DB2".

When I asked him about this he explained that last week (Monday July 17, 2017) the DB2 family had been officially renamed "Db2". The Db2 family is:

• Db2 for i
• Db2 for z/OS (mainframe)
• Db2 for Linux, Unix and Windows

I found that that Db2 page on IBM's website has already been changed, see here.

Now I need to remember to use the new name when writing about it in this blog.

Finding the number of times a character is in a field using SQL

I needed to determine, first, if a certain character was present in a file's field, and then how many times it occurs. Using RPG's file input I would not be able to do this without reading and checking every record's field. Could this be done easier in SQL? Yes.

I am going to give examples of various ways of being able to tell if a certain character is in a field in a file, using increasing complex methods I found. At first I will just give the SQL Select statement for each, and at the end the SQLRPGLE code I created to do this in a program.

Updating one row at a time using SQL

I have been asked to write some more about using SQL embedded in RPG programs. One question I have been asked by several people is how to update a row from a file that had been previously Fetched, just like READ and UPDATE using RPG's native database access. I thought it would be useful to show examples using both RPG native database access and SQL.

First I need a file, as this is for example purposes it very simple, just two fields and one key field:

SQL null byte map as a 2-dimensional array

Nulls are something we are all going to have to get use to handling as we move from DDS files to SQL tables, or start using data from DB2 of i or other non-IBM i databases. Recently I was working on a project with a SQL Table with more than 300 columns. If there was no data in a particular field it was null. If you think about it null is a better alternative than blank or zero as those values could be valid values for the contents of that column.

I have written about handling null in SQL in an earlier post, but in this scenario the method I described to define the null byte map was not practical. I am not going to list 300+ subfields in a data structure array for the null indicators for the matching data structure array I would be moving the SQL Table's data into.