Wednesday, July 26, 2017

Position cursor into field on screens

position cursor on a display file record format

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).

Monday, July 24, 2017

DB2 name change

db2 family renamed

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.

Wednesday, July 19, 2017

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

using sql to count the number of times a character is in a field

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.

Wednesday, July 12, 2017

Updating one row at a time using SQL

update current row/record 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:

Wednesday, July 5, 2017

SQL null byte map as a 2-dimensional array

using a 2 dimensional array for sql null byte map in rpg

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.

Thursday, June 29, 2017

RPGPGM.COM four years old

Wow! I find it hard to believe that I have been writing this blog for four years.

We have been fortunate to share this journey in an exciting time for the IBM i operating system. In all my years of working with this operating system, and is predecessors, there seems to be so much more functionality added every year than there was in the past. During these four years I have written almost 400 posts and pages, trying to share my enthusiasm for IBM i and what it can do.

Wednesday, June 28, 2017

Using relative record number in SQL

sql rrn function to retrieve relative record number from file

I have written about using the Relative Record Number, RRN, in RPG and said that I could not think of a reason why I would ever need to use RRN in one of my programs. Well, I have to take that statement back as I recently found a really good reason for using it. I needed a quick way to retrieve the last record from several different "flat files", and check if it started with the characters "END:". I could do it in RPG, but what is the fun with doing that when I could do the same using SQL?

What is my definition of what a "flat file" is? See here.

I am not describe these "flat files" as it is not really relevant to what I am going to show. I will say that I had a variety of these files from several sources, the layout of the contents is different, and the maximum record lengths are different to. They all have the following in common:

Wednesday, June 21, 2017

Happy birthday AS400

happy 29th birthday as400

Today is the 29th anniversary of the launch of the AS400. It was June 21, 1988, when IBM announced their latest midsize server. You can see a video recording of the announcement here.

At its launch the AS400 server and its OS400 operating were ground breaking.

Tuesday, June 20, 2017

IBM VP reaffirms commitment to RPG and IBM i

ibm vp reaffirms future of rpg

In my opinion it is always good when IBM publishes something about their future commitment to PowerSystems servers, IBM i operating system, and the RPG programming language. Steve Pitcher sent me a copy of a letter, from June 9 2017, by Steve Sibley, the Vice President of IBM Cognitive Systems, that hits this trifecta.

At the start of his letter Steve leaves us in no doubt IBM's regard for RPG:

Wednesday, June 14, 2017

SQL Views for Authorization Lists

views for authorization lists to view user authorities and objects belonging to them

Many companies that use IBM i secure their objects using Authorization Lists. The Authorization List is its own object type, *AUTL. If you have not used or heard of them before I found this good description of them in IBM's KnowledgeCenter.

Like a group profile, an authorization list allows you to group objects with similar security requirements and associate the group with a list of users and user authorities.

Authorization lists provide an efficient way to manage the authority to similar objects on the system and aid in the recovery of security information.

I am not going to discuss in this post how to create Authorization Lists, how to add objects to the lists, or anything similar. I am just going to describe two new SQL Views that were added in the latest IBM i Technical Refreshes, 7.3 TR2 and 7.2 TR6: