Selecting fixed number of random rows in the results

I have written about using SQL's RAND() to generate random numbers to be included in the returned results, but not to return a fixed number of randomly selected results. In other words I just want five randomly selected rows returned in the results.

In this example I have a file, and yes it is a DDS file, that contains just two fields:

• COMPANY: company number
• VALUE: a three long numeric field

For company number 1 there are twenty records with the sequential values 1 – 20.

The request is for, let's say, five randomly selected records for company number 1 only.

New address for IBM's RPG Cafe

In October IBM's developerWorks website started showing an announcement that it would be closing at the end of 2019. Then last month IBM's Barbara Morris made it known that the contents of the RPG Cafe would be moving to another IBM web site.

Good news! The new RPG Cafe is now online with a very long URL, so I will just say click here.

Having had a quick glance at it, it appears that all of the same information that was available in the old version is also in the new. I have to say I prefer the user interface of the new site.

A big thanks to IBM, and everyone else involved with this, for preserving the RPG Cafe information.

Equivalent of DSPPGM and DSPSRVPGM using SQL part 2

At least once a day I use the Display Program command, DSPPGM, and the Display Service Program command, DSPSRVPGM, to look at the service programs and modules bound to ILE programs and service programs I am analyzing. While the command give me the information I need the latest Technical Refreshes, IBM i 7.4 TR1 and 7.3 TR7, gives me another way to get the same information from two new SQL views:

1. BOUND_MODULE_INFO
2. BOUND_SRVPGM_INFO

In this post I am going to describe how I would use them to replace what I do with DSPPGM and DSPSRVPGM commands, and a few other pieces of information I have found that these Views make it easy for me to get to.

Equivalent of DSPPGM and DSPSRVPGM using SQL part 1

I am sure we are all familiar with the Display Program, DSPPGM, and with the Display Service Program commands, DSPSRVPGM as a way to get all sorts of information about the program or service program entered. My two biggest complaints about these commands are:

1. I can only get the information for one program at a time
2. The only output options offered are display or print, no output to file

With the latest Technology Refreshes, IBM i 7.4 TR1 and 7.3 TR7, there are a number of new Db2 for i, or SQL, Views to give me the same information I was getting from the commands.

In this post I will be describing two of these Views:

Using SQL to write to the job log

Another useful addition to IBM i with the latest round of Technical Refreshes, 7.4 TR1 and 7.3 TR7, is a SQL function that allows you to write directly to the job's job log.

Why would I want to write to the job's job log?

I would use this to write to the job log when something I would expect to happen did not. Or as a record that some part of the program ran, and completed successfully or failed.

The syntax for this function could not be simpler:

CALL SYSTOOLS.LPRINTF(string or variable)

Data Queues using SQL

The latest Technical Refreshes, IBM i 7.4 TR1 and 7.3 TR7, included four additions to SQL that allow us to do things with Data Queues.

In this post I will be describing how I would do things with data queues pre-the latest TRs and post. These are:

1. DATA_QUEUE_INFO view
2. CLEAR_DATA_QUEUE procedure
3. SEND_DATA_QUEUE procedures (there is more than one and I will describe the differences below)
4. RECEIVE_DATA_QUEUE table function

But, before I start describing any of the above I am going to need to have a data queue I can use. Here is a CL program I wrote to create my data queue: