Wednesday, May 24, 2017

Determining the screen size

determine screen size if it is *ds3 24x80 or *ds4 27x132

Most of us are aware that TN5250 sessions (displays) on the IBM i can be configured in two sizes:

  • 24 x 80 commonly known as *DS3
  • 27 x 132 commonly known as *DS4

Most of the time IBM i operating system handles this for us, only displaying "wide" screens when my session is *DS4 and the information to be displayed is wider than 80 columns.

Tuesday, May 23, 2017

My favorite CL shortcuts

using cl shortcuts rather than long hand code

If I am going to write and give examples of programming in CL I need to start by explaining some of the CL language shortcuts I use. Perhaps "shortcuts" are not the right word, maybe "shorthand". Oh well, I am sure you will work out what I mean as you read this.

I use these shortcuts extensively in my CL code as for a couple of reasons:

  1. I think it is easier for someone else to understand the code I have written.
  2. It is just quicker to write, the faster I can write code the more I can get done.

I am going to start with my favorite three.

Wednesday, May 17, 2017

Defining LDA in free format RPG

how to define the lda in a free format rpg program

It has been pointed out that this web site lacks a good description of how to retrieve the data from the Local Data Area, LDA, in the post about defining variables in free format RPG. I agree, which is why I have written this about retrieving and updating the LDA.

I am going assume that we all know what the LDA is. If you do not then you can read IBM's definition of what it is.

There are two common ways to bring in and update the data from the LDA in fixed format RPG.

Monday, May 15, 2017

Why is my RPG program not writing to the file?

rpg output buffer

I have been asked this question a lot recently:

When I am in debug my RPG program does not write to the file. What is wrong?

I have decided to write this post so I can, in the future, refer people here.

Let me give a very simple example RPG program so I can explain what is going on.

Wednesday, May 10, 2017

Using SQL for message queue data

new view for viewing messages in message queues

One of the new enhancements that came with the latest TRS for IBM i 7.3 and 7.2 is a new SQL View: MESSAGE_QUEUE_INFO. This view returns one line for each message in a message queue, in a similar manner to what is returned by the Display Messages command, DSPMSG.

This will allow me to have a way to quickly, and easily, search a message queue for a message. I must have *USE authority to the message queue, and *EXECUTE authority to the library it is in. One thing to remember is that message queues do get full, and when they do messages from them will be deleted. Also certain message queues are cleared when the IBM i partition is IPL-ed. If you are looking for a message that may have been issued sometime ago you might have better luck searching the History log via SQL.

Wednesday, May 3, 2017

Viewing object authority using a SQL view

getting authority data from object_privileges view rather than dspobjaut or edtobjaut

One of the new SQL Views added with the latest Technical Refreshes for IBM i, 7.3 TR2 and 7.2 TR6, is going to be very useful to me. Once a year, at audit time, I am asked to produce a list of all objects within the production library list that are not adequately secured. With the new Object Privileges SQL view I can generate all of the information I need in minutes, using a few SQL statements. This is going to save me a lot of time and effort.

The Object Privileges view, OBJECT_PRIVILEGES, like many of the new Views is to be found in the library QSYS2. The information it contains is the same as the information I can generate using in the Display Object Authority command, DSPOBJAUT. Rather than list all of the columns I will list them when I use them in various SQL statements. If you want to see a full list of all the columns visit the link I have provided a link to the IBM documentation for this View at the bottom of this post.

Tuesday, May 2, 2017

Second parameter added to SQL's LTRIM and RTRIM

2nd parameter added to sql trim built in functions rtrim and ltrim

As part of the goodies that came with the recent Technical Refreshes, TR, was the addition of a second parameter to SQL's Left trim, LTRIM, and Right trim, RTRIM, built in functions. The second parameter has the same functionality as it does in CL and RPG's trim built in functions, when used trimming particular character from either the left or right of the string.

The syntax of these SQL functions is remarkably similar to that of the CL built in function:

Wednesday, April 26, 2017

Using SQL to aggregate columns into one returned result

aggregating multiple values into one result set using sql

There are times when I have want an easy way to put values from a file, or table, "horizontally" into one column rather than vertically with more than one row.

"Vertical" "Horizontal"
TYPE        THING
ANIMAL     ELK
ANIMAL     HAWK
ANIMAL     MEERKAT
ANIMAL     ORCA
TYPE       THINGS
ANIMAL     ELK, HAWK, MEERKAT, ORCA, SEA L
FRUIT      APPLE, FUJI, BLACKBERRY, GRAPEF
VEGETABLE  SQUASH

Wednesday, April 19, 2017

Min and Max built in functions added to RPG

using the rpg min and max built in functions

A pair of introductions to RPG as part of IBM i 7.3 TR2, and 7.2 TR6, are the minimum and maximum built in functions, %MIN and %MAX. The maximum built in function returns the greatest value in a list of variables and/or values. The minimum returns the lowest value from a list of variables and/or values. Otherwise the way they are defined and the rules governing them are the same.

To use these functions there must be at least two values, and they must be of the same type. What I mean is that all of the values must be some type of numeric, character, date, time, or timestamp. I cannot mix types in the values. Pointers cannot be used.

They are so simple I can go straight to examples of using them. Let me start with a variety of numeric data types:

Thursday, April 13, 2017

Change to SQLRPGLE compile listings

type of rpg used in sqlrpgle compile listing changed to free format

Something I have noticed since the installation of IBM i 7.3 TR2 and 7.2 TR6 on the partitions I use, is a change to the compile listings of SQLRPGLE programs.

The process to create an object from a SQLRPGLE source member is a multi-step process:

  1. The syntax of the SQL within the source member is checked to ensure it is valid.