CICS allows us to access file data in many ways. Most file accesses are random in online system as the transactions to be processed are not batched and sorted into any kind of order. Therefore CICS supports the usual direct access methods − VSAM and DAM (Direct Access Method). It also allows us to access data using database managers.
Random Access
Following are the commands which are used for random processing −
| Sr.No | Commands & Description |
|---|---|
| 1 | READ
READ command reads data from a file using primary key.
|
| 2 | WRITE
Write command is used to add new records to a file.
|
| 3 | REWRITE
REWRITE command is used to modify a record that is already present in a file.
|
| 4 | DELETE
DELETE command is used to delete a record that is present in a file.
|
Sequential Access
Following are the commands which are used for sequential processing −
| Sr.No | Commands & Description |
|---|---|
| 1 | STARTBR
STARTBR is known as start browse.
|
| 2 | READNEXT / READPREV
When we issue a STARTBR command, it does not make the records available.
|
| 3 | RESETBR
The RESETBR command allows us to reset our starting point in the middle of a browse.
|
| 4 | ENDBR
When we have finished reading a file sequentially, we terminate the browse using the ENDBR command.
|
No comments:
Post a Comment