Levels Numbers in COBOL

-
level number are play very important role in declaration of the variables in the COBOL.


level number are describe the hierarchy of data in the COBOL.

level number available are   01 to 49 , 66, 77 and 88.

level number are two types based on the usage.

General purpose level number.
Special purpose level number.

General purpose level number:

 In this level number are start with low number 01 and  maximum number is 49.

Based on this level number, the data items/variables are divided different categories.

1.Individual data item.
2.Group data item.
3.Elementary data item.

Individual data item:
it is a data item which will be the only one variable declaration.
it has picture clause and no sub items.
individual data item are unique number in the  program.

example:

01              WS-NAME       PIC             A(10).
02              WS-CLASS      PIC             9(02).
49              WS-RANK     PIC                9(01).

Note : there is no elementary  data items under it and level number from 01 to 49.

Group data item:

 it is a data item which will be the  first variable declared.

group data item don't have picture clause and it has elementary data item.

example:

 01  BILL-PRINT-FIXED-AREA.  -----------------> group data item.              
    15  BPF-INV-NR        PIC X(15).  ----------------------    elementary data item
    15  BPF-INV-DT        PIC X(10).   ---------------------    elementary data item
    15  BPF-INV-TM        PIC X(4).     ---------------------   elementary data item.

note: group data item level number start from 01 to 48.

Elementary data item:

 it is a part of group data item and it has a picture clause.

elementary data item level number start from 02 to 49.

in above example under group data item are elementary data item.


Special purpose level number:

special purpose level number are below:

66 ----->    used for  Rename clause.
77------>   individual elementary data item.
88-------> used for condition names


88 level number:

It used as like if condition.

For example.

10  DAYS           PIC X(10).
    88  MONDAY      VALUE '00'.
    88  TUESDAY      VALUE '10'.
     
In this above example "DAYS" expected the data from end user and it's  check with below conditions which  is by 88 level number.

77 level number:

 Elementary level item. Cannot be subdivisions of other items (cannot be qualified), nor can they be subdivided themselves.


 What is the difference between level 77 and 01? And which is more efficient? 
Level 77 can be used to describe independent elementary items in the Working Storage or Linkage Sections. Level 77 cannot use Redefines.

Level 01 can be used to describe both elementary and group items. Any item described in Level 01, the system is putting on Double-Word boundary and inserts slack bytes if necessary



Comments

Post a Comment

Popular posts from this blog

COBOL + DB2 complication process.

-
Image
There are various step involved before we run/execute a COBOL + DB2 program.   Below step are the various steps.   Precompile.   Compile.   Link edit.   Bind.   Package & plan. Step 1: Precompile               COBOL compiler did not understand about SQL statement so, it undergoes to precompile. In precompile.     Expands all include copybooks which are written in program.     Extracts all SQL statements into DBRM and SQL statement are convert into call statements.    Generates time-stamp for modified source codes and DBRM .there are checked at run time.   Check syndicated error of SQL statements and validates the fields based on the table declaration from dclgen copybook.    Notes: precompilation process can be executed even if DB2 is down. DSNHPC    ----------- It is the program used for precompilation. Step 2:  Compile            It is same as normal COBOL compilation.it takes modified source as input and compilers.  IGYRCTL --
Read more

ABEND list for JCL

-
what is ABEND?   An ABEND (abnormal end) is an exception condition which results in the abnormal termination of a program or software. It is a common terminology used in the mainframe world where a JCL terminates with an error code.  S0CB -    Attempting to divide by 0 and not using ON SIZE ERROR S002 -    Very large record length/ wrong record length Sx22 -   Job has been cancelled. The value of x will vary depending on the way the job was  cancelled. . S222 -    Means job was cancelled by a user or operator without a dump.                If a TSO session times out you will probably get an S522 ABEND code. S222 -    The job was cancelled (by subsystem or operator) because it violated               Some restriction. S522 -    JOB or TSO session exceeded maximum job wait time OR               Operator did not mount the require tape within allowed time limit    S806 -    Load module not found SB37
Read more

difference between jes2 and jes3

-
JES2 JES3       1.        Decentralization.       2.        Every processor the incoming job individually.       3.        It is prestep allocation.       4.        Dataset allowed before step is executed.       5.        It is a local process.       6.        Control statement (//*). 1. Centralization. 2. It control process and assign job to sub processor. 3. It is prejob allocation. 4. Dataset allowed before job is schedule. 5. It is global process. 6. Control statement (/*).
Read more