Random Access
By providing the key value, records can be accessed randomly from any point in the file. Only Indexed and Relative files can be used in this mode.
- For indexed files, records are retrieved in accordance with the key field value.
- Records are retrieved for relative files in accordance with the value specified in the relative key.
Cobol
IDENTIFICATION DIVISION. ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT GFGFILE1 ASSIGN TO DISK ORGANIZATION IS INDEXED ACCESS MODE IS RANDOM RECORD KEY IS GFG-KEY1 IDENTIFICATION DIVISION. ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT GFGFILE1 ASSIGN TO DISK ORGANIZATION IS RELATIVE ACCESS MODE IS SEQUENTIAL RELATIVE KEY IS GFG-KEY1 |
File Access Modes in COBOL
COBOL an acronym for Common Business Oriented Language is a computer programming language, which was designed for business use. In COBOL, file access modes are used to specify how to access data from various file organizations according to requirements. In COBOL, there are 3 types of file organization:
- Sequential: Records that are stored and accessed in sequential order.
- Indexed: Records that can be accessed both directly and sequentially.
- Relative: Records are arranged according to their relative addresses.
Different file access modes can be used to access the data within the file for each file organization scheme. The following are the various access modes provided by COBOL:
- Sequential Access
- Random Access
- Dynamic Access
The below table shows the file organizations and the access modes of files:
| File organization | Order of records | Access mode |
|---|---|---|
| Sequential | Order in which they were inserted | Sequential Access |
| Indexed | Based on the value of the record key | Sequential, Random, Dynamic Access |
| Relative | Order of relative record number | Sequential, Random Dynamic Access |
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