Configuring database connection between two IBM i

In my day job I work in an environment where there are multiple PowerSystems servers, and many of them have multiple IBM i partitions. I was tasked to gather information from most of the partitions into one location. I decided to use SQL to fetch the information from the various sources.

I used the following two methods to connect to the other partitions using the partition name:

CONNECT TO SYSTEM2   or   SELECT * FROM SYSTEM2.OTHERLIB.RMTFILE

When debugging my program I found that when I tried to connect to some of the partitions I received a SQLCOD value of -950 and the following message:

New Technology Refreshes are coming

In the past the twice yearly Technology Refreshes updates for the current releases of IBM i were announced in the middle of February and the beginning of October, to coincide with Common USA events.

While Common does not appear to have a Spring conference this year (at the time I am writing this post their website is unavailable), the announcement of IBM i 7.3 TR4 and 7.2 TR8 could still be on track for this month as I have found empty pages for them in IBM developerWork's website.

Getting the library list from a Job Description

The germ for this post came from this question:

How can get the Library List from a Job Description?

I can use the DSPJOBD command to see the Job Description's library list, alas I can only display or print it. This does not make it easy for me to use in a program.

DSPJOBD JOBD(MYLIB/MYJOBD) Display Job Description Job description: MYJOBD Library: MYLIB Initial library list: Sequence number Library 10 QTEMP 20 MYLIB 30 ANOTHERLIB 40 QGPL

SQL Views to list SQL programs and the statements within them

I found these two Views when going through the list of Db2 for i Views on Scott Forstie's Db2 for i poster (if you have not printed this out and stuck it to your wall do so now!). Both contain information about programs containing SQL statements:

1. SYSPROGRAMSTAT:  One row for each program that contains a SQL statement
2. SYSPROGRAMSTMTSTAT:  One for each SQL statement in a program

There are a couple for gotchas I found working with these Views, which I was disappointed by, I will mention these shortcomings when I discuss the View in detail below.

Using RPG data structures with SQL insert and update

As I can fetch rows using SQL from a table, or file, into a data structure. I was asked:

Can I insert or update rows using a RPG data structure?

The answer is a definite "Yes".

In these examples I am going to be inserting and updating the following table:

01 CREATE TABLE QTEMP.TABLE1 ( 02 COLUMN1 CHAR(10) NOT NULL, 03 COLUMN2 DECIMAL(11,2), 04 COLUMN3 DATE, 05 COLUMN4 TIMESTAMP 06 ) ;

Displaying more than one subfile at a time

I decided to write the post after being asked if I had an example of having two subfiles on the same screen. I did a quick search using Google and was unable to find what I considered a good example I felt comfortable sharing.

In this example I am going to show two subfiles horizontally (i.e. one on top of the other). I could have shown them vertically (next to one another), or even had more than two. The principals I show here can easily be adapted to fit either of those other scenarios. The most important thing to remember is that each set of subfile and subfile control record format cannot overlap another.

To reduce the size of the display file source code, shown here, I have removed all unnecessary color and display attributes codes that I use in the screens I build. I am going to show my display source in multiple parts to make it easier to understand what each record format is for. Let me start with the file level keywords.

Determining length of a string using SQL

This is just a quickie in response to a question I was asked: How can I determine the length of string within a column using SQL?

This is very simple as there is Db2 for i scalar function to do this LENGTH. But before I do that let me explain why using this scalar function is simpler than doing the same using RPG.

I have a simple DDL table of just one column. There is no "NOT NULL", therefore, this column can be null.

CREATE OR REPLACE TABLE QTEMP.TESTFILE ( FIELD1 VARCHAR(80) ) ;

And it contains the following data:

Welcome to 2018

At the start of a new year I am always excited about what it will bring, and grateful what the old year brought.

The past few years have been a really exciting time to be involved with the IBM i world. In my opinion the twice yearly Technical Refreshes has allowed IBM to bring us new things without us having to go the through upgrading to a new release. My favorites of last year's, 2017, introductions were additions to Db2 for i:

• JOB_QUEUE_INFO
• LIST_AGG
• MESSAGE_QUEUE_INFO

What were your favorites of the 2017 introductions?

If you need a reminder check these links:

Signed numeric in CL data structures

The germ for this post comes from a question I was asked. The questioner was passing a file record as a data structure from a RPG program to a CL program, and when they looked at the data structure the CL program would "really mess up" some of the numeric data structure subfields. After further questioning I discovered the "messed up" fields we all signed numeric fields. Once I established that I knew what the problem was, and came up with a simple solution.

Let me show what the problem is, and then the solution I came up with. Let me start with the file, you will not be surprised to discover that I called it TESTFILE.

Using alias for data structure subfields

Have you ever used a file or table to externally define a data structure, and then wondered how to use the alias field/column names rather than the short ones?

Fortunately it is simple to do. But, before I start with showing the file and table I will be using in these examples. Let me start with the file, TESTFILE:

A R TESTFILER A F001 7A ALIAS(FIRST_FIELD) A F002 7P 2 ALIAS(SECOND_FIELD) A F003 L ALIAS(DATE_FIELD) A F004 T ALIAS(TIME_FIELD)

Using SQL to get information about ASP capacity

Someone asked me if there was an easy way to monitor the available storage space in their Auxiliary Storage Pools (ASP)? I have to admit this is something I have not been asked before, and not something I worried about. I knew we were getting close to critical storage when I would receive the message from the system operator asking what could be deleted from the system before that was reached.

Fortunately in the latest round of Technology Refreshes, IBM i 7.3 TR3 and 7.2 TR7, a new Db2 for i View was added to return information about the ASP.

The new View, ASP_INFO, is one of a pair of additions to Db2 for for ASP monitoring. Like all the recent additions to Db2 for i this View is found in the library QSYS2. I am not going to list all the columns here, as I will only using a few in this example. If you want a list of them all you can go to IBM's KnowledgeCenter here.

Resolving "array X not defined or not usable"

I have shared my example of using a multiple row fetch as an efficient way to get multiple records/rows at once, and place the fetched data into a data structure array. To save myself time, and effort, I don't enter all the fields from the file/table as subfields, I use the file/table to externally define the data structure. Many of my colleagues where I work, and many of you, use this method as it makes things like programming subfiles so easy.

Every once in a while someone comes to me with, what I can only describe as a cryptic, message in the SQL precompile listing: