User:Heiko

About

This is Heikos personal page, in which he maybe shares some private information or collects bits for new articles.

Personal information

Heiko has been in IT since the 90s, but never worked with an AS/400...until 2019. He'll document his first steps in the hope they will be useful to others.

Sandbox

Screen mit MW-Bordmitteln:

                                  Anmelden            
                                              System  . . . . . :   SLVRLAKE
                                              Subsystem . . . . :   QINTER
                                              Bildschirm  . . . :   QPADEV0004

               Benutzer  . . . . . . . . . . . .             
               Kennwort  . . . . . . . . . . . .
               Programm/Prozedur . . . . . . . .             
               Men}  . . . . . . . . . . . . . .             
               Aktuelle Bibliothek . . . . . . .             













                                       (C) COPYRIGHT IBM CORP. 1980, 2013.

<console> Test </console>

<console>

                                  Anmelden            
                                              System  . . . . . :   SLVRLAKE
                                              Subsystem . . . . :   QINTER
                                              Bildschirm  . . . :   QPADEV0004

               Benutzer  . . . . . . . . . . . .             
               Kennwort  . . . . . . . . . . . .
               Programm/Prozedur . . . . . . . .             
               Men}  . . . . . . . . . . . . . .             
               Aktuelle Bibliothek . . . . . . .             













                                       (C) COPYRIGHT IBM CORP. 1980, 2013.

</console>

Ideas for new articles

Project Hello World

Preparations

Things you need:

• An working tn5250 terminal, connected and logged in
• maybe this as a primer or quick reference:
  • Basic Commands
  • UNIX-User's Cheater Table
  • How to program an Application

Creating a physical file to hold the sources

Every user has a personal library, like a home in an Linux environment. Since a user can have and use multiple libraries, the current (=default for all operations) is stored in *CURLIB. Because the value of *CURLIB can be changed by the screen you are currently working in, all following commands will contain my personal library name HKRETSCHME. If you are sure *CURLIB is set correctly, you can omit the library.

This command creates a physical file named HELLO01:

CRTSRCPF FILE(HKRETSCHME/HELLO01) RCDLEN(112) TEXT('Project Hello World')

But I prefer to do this in more steps, which I'd recommend to every beginner (By the way: don't bother using cases, the AS/400 won't either. Using capital commands and names just makes it more readable in this article.):

CRTSRCPF

If you don't give any parameters for this command, you will be asked. This works great for CRTSRCPF, but in general, OS/400 will only ask for necessary arguments. Some commands, like CHGUSRPRF will just do nothing. This always works:
Enter the command you want to execute and then hit F4.

A small detour: Physical Files?

Heiko struggled a lot with this and thinks a small introduction is necessary:

• Libraries: Every user has his own personal library, think of it like a Linux home directory. Details
• Physical Files: Of course this is no physical file and you can't touch it. And don't think of if (like I as a german do) as one file (f.e. /etc/passwd), it's more like an collection of informations, like you might know from MacOS resources.
• Members: A member is a file in an physical file, like a book in a filing box. Members of a physical file share the given structure of the PF. Record structure, field lengths, etc.

A more visal approach of explaining:

The Library is the room you keep your Physical Files (like filing boxes) in. The Physical Files contain Members (like books) but must be the same size (okay, a crude explanation for the "must share structure" approach).

• You can have as much rooms, filing boxes and books as you want.
• But you can't put rooms in rooms, boxes in boxes or books in books.
• The AS/400 has no tree-like storage structure, it is just a list (of Libraries) with a limited depth (Physical Files and Members) to unfold:
  

Creating the database

The procedure is as follows:

• create a text file describing the database
• compile it into a database

Creating the DDS

The textual description of a database is called DDS. You can learn more here.

• Input this to work with our just created Source Physical File:
  
  wrkmbrpdm file(hkretschme/hello01)
• Hit F6 to create a new member:
  
• This will run STRSEU:
  (Input member and type)
  
• Which brings you to SEU:
  (Enter text as shown)
  File:Hello01wrkmbrpdm03.png
  Here's what it means:

        ***************** Datenanfang *******************************************************************************************
0001.00      A          R MESSAGES                                                                               191001           means: Add Record named MESSAGES
0002.00      A            TEXT          42A                                                                      191001           means: Add field named TEXT with 42 bytes of Ascii.
        ******************Datenende *********************************************************************************************

• Enter Y (here: J) to save the member.
  
  After saving, check the lower lines for messages. If there is a synthax error, return to SEU and check every line.
  Hint: Use F4 for assistance while coding!

Creating the database physical file

• While working with PDM, enter 14 to compile the database.
  
• The compiling will be queued…
  
• …and you have to check with DSPMSG if it was successful or not

Hint: Checking my messages with DSPMSG only showed me it wouldn't compile. No error message or any other useful information. If you run into trouble, double check your DDS in SEU, using F4 on every single line. And remember the AS/400 is picky. Even an empty line is enough cause to abort compilation.

• If compilation worked out, you can see your compiled database physical file here:
  wrklib + <F4>
• Enter 5 to show contents of your library
• And here it is:
  
  It is named HELLO, named after the DDS Member we compiled.

Insert content into the database

TBD

Display the content

TBD

TODO: --> Beginners Project: Hello World (using database and display file)

Articles to maintain

• Beginners Project: 99 Bottles Of Beer (using REXX)

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• Links
  • Basic Commands
• References: