IMS allows applications to read and update IMS databases using database calls issued in DL/I. An application can retrieve, replace, delete, and add segments to the database, provided the application has authority to access the segment.
In Smalltalk, all of the database calls exist in one class: IMSDBRequester. Below is a description of the class and instance methods available in IMSDBRequester, along with details on how to use a database call in Smalltalk and restrictions on call usage, where applicable.
See IMS/ESA Application Programming: DL/I Calls for the following information:
Note: | The IMSDBRequester uses the PCB to maintain your last position within the database. |