IBM i objects share similarities with objects in object-oriented programming, but there are differences as well. There are similarities in that when storage is allocated for something, that something is of a specific type, and only a specific set of programs are allowed to act upon that object. There are differences in that even though IBM i supports Java and C++, IBM i objects cannot be inherited like the classes in those languages. Another difference is that the set of object types is fixed by IBM, and only IBM has the ability to create new ones.
The number of object types is huge and a small subset of them are available to users. The human readable form of the object type is always a three to six character mnemonic preceded by an asterisk. What follows is a short list of the more commonly used objects and their mnemonics:
Creating an object usually (but not always) involves a command that begins with the mnemonic "CRT". So, to create a job description you would prompt the CRTJOBD command. User profiles would be created with the CRTUSRPRF command. Similarly changing objects is done by prompting commands preceded by "CHG" (CHGJOBD, CHGUSRPRF, etc.), deleting an object uses "DLT" (DLTJOBD, DLTUSRPRF, etc.), displaying an object uses "DSP" (DSPJOBD, DSPUSRPRF, etc.), and working with a set of objects uses "WRK" (WRKJOBD, WRKUSRPRF, etc.). To view a generic set of objects in a library use the DSPOBJD command. WRKOBJ can be used to view objects in multiple libraries.
The IBM i command structure focuses on ease of use. In order to view all the objects that the verb portion of an IBM i command can work ("WRK") upon the "go cmdWRK" where "WRK" may be any of the verbs current and future "CHG","DLT","DSP","EDT","INZ","PRT" etc. Parameters for the command can be displayed by simply typing the command name and pressing F4 or by typing the command name on an IBM i command line. This will prompt a standard SAA panel providing prompt information for each parameter the command can accept. The command string can be displayed at any point during prompting by pressing F1u2, which if used to exit from the command prompting can be utilized by the F9=Retrieve previous command. A help summary for the command and its parameters can be obtained by pressing F1.
This command structure and strict adherence to the S.A.A. standards make the IBM i extremely easy to use from at command level and also to develop source files containing commands. Commands may be executed interactively or placed in text files and executed in sequence or can be compiled into an IBM i object of type *PGM, with a type-attribute of CLP.
Edited: 2021-06-18 19:28:16