IMS DB Management Calls

IMSDB Command Codes IMSDB Functions

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DL/I calls used to perform data management functions with IMS DB in application program.

Data management function can perform operations like READ, INSERT and INSERT etc,.

Database calls must be either DB PCBs or AIB parameters (which will be discussed in further topics).

The below is the list of functions that can be performed on the database.


Function Code Meaning and Use Options
GN Get Next Segment in sequential order

Retrieves subsequent segments sequentially.

Call with Get Next (GN) is used to retrieve segments sequentially from the database.
GNP Get Hold Next segment in Parent

Retrieves dependent segments sequentially.

Call with Get Next in Parent (GNP) is used to retrieve dependent segments sequentially.
GHN Get Hold Next Segment.

Retrieves subsequent segments from the database

Call with Get Hold Next (GHN) is the holding segment for a GN call.
GHNP Get Hold Next segment in Parent

Retrieves dependents sequentially.

Call with Get Hold Next in Parent (GHNP) is the hold segment for the GNP call.
GU Get Unique Segment.

Retrieves unique segments and establishes a starting position in the database

Call with Get Unique (GU) is used to directly retrieve segments.

And also to establish the starting position in the database for sequential processing.
GHU Get Hold Unique Segment

Retrieves matching segments and establishes a starting position in the database.

Call with Get Hold Unique (GHU) is the hold segment for a GU call.
ISRT To insert the segment.

Used to loads and adds one or more segments to the database

The Insert (ISRT) call is used to load a database and to add one or more segments to the database.

And also ISRT used to add a record to the end of a GSAM database.
REPL Replace the segment.

Changes values of one or more fields in a segment.

The Replace (REPL) call is used to change the values of one or more fields in specified segment.
RLSE Release Locks on Segment.

Releases all locks held for unmodified data.

The Release Locks (RLSE) call is used to release all locks held for unmodified data.
DLET Delete segment.

Removes specified segment

It also removes all its dependents from the database

IMSDB Command Codes IMSDB Functions

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