General rules for establishing naming conventions

Good naming conventions are mandatory in a data processing project, especially in an environment with multiple applications.

A good naming convention includes the following general rules:

Each name must be unique. If names are not unique, unpredictable errors can occur.
Each name must be meaningful and identify to all personnel the type of resource that the named element is.

The following table provides an example of basic naming conventions. These conventions are only an example, and you can establish your own naming conventions.

Table 1. Example of basic naming conventions
Resource type	Convention
SYSTEM	S as first letter
JOB	J as first letter
PROGRAM	P as first letter if this is an IMS program (to match PSB) G as first letter otherwise
MODULE	M as first letter
COPY	C as first letter for a member that contains the segment structure A as first letter for a member that contains all the SSAs for the segment Other members must be the same as the segment name
TRANSACTION	T as first letter
PSB	P as first letter
PCB	Same name as PSB Note: The PCB occurrence number indicates the position of the PCB in the PSB
DATABASE	D as first letter with the subsequent characters identifying the type of database and its relationship to other databases. For example, D`taaann`, in which the characters `taaann` indicate the following:
	Character	Meaning
	`t`	Database type. The database can be one of the following types: P Physical L Logical X Primary index Y Secondary index
	`aaa`	A unique database identifier common to all logical and index databases based on the same physical database
	`nn`	A unique identifier, if there are multiple logical or secondary index databases
SEGMENT	S, R, or O as first letter with the subsequent characters identifying the type of segment and its relationship to its database. An R identifies 'segments' that are non-DL/I file record definitions. An O identifies any other data areas, for example, terminal I/O areas, control blocks, report lines, and so on. For example, S`aaabbbb`, in which the characters `aaabbbb` indicate the following:
	Character	Meaning
	`aaa`	A unique database identifier; same as the physical database in which the segment occurs Note: Concatenated segments should have an aaa value corresponding to the aaa of the logical child segment.
	`bbbb`	An identifier for the user name
ELEMENT	E as first letter