Thursday, January 20, 2022

SQL is your friend

Today I had a minor task to implement.  The task was to initialise some new data in a file.

Typically, I would write a program as an EXCEXTFUN and do my processing via standard 2E code.  The problem with little data update programs is that unless you manage them well (i.e. remove them, label them so you can ignore them etc), they start to clutter the model.  On the other hand they are handy to have around in case someone needs to do something similar in the future.

However, unless you are a software house, you probably don't care too much that this 'product field' was initialised 8 years ago by xyz user.

That all said and done, my task was to insert a data record and there were some fields that needed to be initialised that contained the business data, and, there was also an AUDIT STAMP for the INSERT.  If you don't mind me saying, it was quite a convoluted one at that too with numerous fields.  This AUDIT STAMP required a User, Date, Time, Job Number and Job Name among other fields.  With 2E all of these are simple to MAP and are available to us via the JOB context.

My task was to implement the data without adding to the setup/fix program maintenance burden and on this occasion we have a few choices.

  1. Write a document explaining to the implementer how I want them to add a record. Either by a YWRKF hack or perhaps a user screen.
  2. Give them a small data file and ask them to CPYF the records into the target file as *ADD.
  3. Write that 2E program I spoke of above and get them to call it.

Or, as I did in this instance.  

    4. Simply give them a line of SQL I wanted them to execute.

Sweet, job done, but how do I initialise the 2E formatted date, or get the current system date and time from the machine and, where do I get the JOB details from that are so easily available within 2E code via the JOB context.

The answer is as follows: SQL has what it calls global variables (Blue) and functions (Red).  It just turns out that some of these are useful for me to update my fields in the AUDIT STAMP.

In order to initialise my fields I just substitute my insert data with the following:-

User Profile = USER
Date = DEC(CURDATE())-19000000
Time = DEC(CURTIME())
Job Number = LEFT(JOB_NAME,6)
Job Name = SUBSTRING(JOB_NAME, LOCATE('/',JOB_NAME,8)+1,10)

You will note that to get the 2E DTE format we simply minus the 19000000.  For the standard TIME and USER fields we just use the variables without any manipulation.

For Job Number we need to extract the data the JOB_NAME variable.  Usually this is formatted as 123456/LDARE/QPADEV0001 for example.  However, for people with longer names it could be 654321/PLONGNAME/EOD, also the job running the task may not be an interactive screen if it was submitted for example.

This means that to get the job name data from the JOB_NAME SQL global variable we need to call a little function that locates and substrings all the data after the 2nd '/'.  Given that the JOB_NUMBER is always 6 long I've just arbitrarily started from the 8th character.  I could have embedded more LOCATE calls to replace this hardcoded value, but as always, time was against me.

Hopefully, in the future if you need to update a table via SQL, but were put off by now knowing how to get at some of these global variables, the above will stick in your mind.

Thanks for reading. 

Lee.

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