JCL structure is nothing but how the JCL can be coded.
JCL structure defines the predefined way of JCL creation.
JCL contains two parts in Structure.
- JOB Card
- JOB Body
JCL structure like below.
JOB | | EXEC | | DD
Let's discuss one by one.
1. JOB Card:
JOB card is nothing but JOB identity.
JOB card is the first statement to the JCL
JOB card has the accounting information and job related information.
JOB card coded only once in the JCL.
JOB card is the first control statement in the COBOL.
JCL requires JOB card to identify the JOB.
JOB card used to make the OS also makes aware of the JCL.
JOB card started with slashes (‘//’) in the first line and can continue in the second line. But no continuation in 72th column not required when continuation required.
JOB card parameters can be divided into two types
The parameters which are very specific to its position in JOB card called positional parameters.
Positional parameters information need for OS.
Positional parameters starts immediately after JOB operation specified.
Positional parameters starting position is 16th column.
Positional parameters are mandatory.
Positional parameters can be explained in detail here .
The parameters apart from positional parameters used in JOB card called as Keyword parameters.
All Keyword parameters are optional.
Keyword parameters can be coded in any order.
Keyword parameters follow programmer name.
Each keyword parameter separated by comma (,).
Keyword parameters can be explained in detail here .
2. JOB Body:
JOB Body contains the combination of steps.
Each step may contain executable statement and Data Definition statements.
JOB Body can be divided into two parts.
Let’s discuss each part one by one.
EXEC statements have details of the program/procedure to be executed.
Maximum 255 steps can be coded in single JCL.
EXEC statement describes the beginning of the step.
Step name should be starts from 3rd column of length 8 characters.
EXEC statement can be explained in detail here .
DD stands for Data Definition.
DD specifies the data set to be used in the JOB step.
DD also responsible to provide the specification about how to use of the data set.
DD statement is left justified.
DD statement can be explained in detail here .
If any questions on the above, post your queries on Jcl Discussion forum
JCL Coding Sheet JCL Job Card