Below is a list of eleven IMS DB interview questions useful for beginners. This is my second set of questions.
1) How CICS access IMS DB database?
Access through CICS command level interface
2) How REXX Exec access IMS DB?
REXX EXECs can invoke IMS functions by using the IMS adapter for REXX.
3) What is ICAL call in IMSDB?
The IMS Call (ICAL) call is used by an IMS TM-managed application program to send a synchronous processing request to a service that runs in a z/OS or distributed environment.
4) What is DFSDDLT0 in IMS DB?
DFSDDLT0 is an IMS application program test tool that issues DL/I calls to IMS based on control statement information. You can use it to verify and debug DL/I calls independently of application programs. You can run DFSDDLT0 using any PSB. You can also use DFSDDLT0 as a general-purpose database utility program.
5) The functions that DFSDDLT0 provides include the following:
Issuing any valid DL/I call against any database using the following:
- Any segment search argument (SSA) or PCB, or both
- Any SSA or AIB, or both
- Comparing the results of a call to expected results. This includes the contents of selected PCB fields, the data returned in the I/O area, or both.
- Printing the control statements, the results of calls, and the results of comparisons only when the output is useful, such as after an unequal compare.
- Dumping DL/I control blocks, the I/O buffer pool, or the entire batch region.
- Punching selected control statements into an output file to create new test data sets. This simplifies the construction of new test cases.
- Merging multiple input data sets into a single input data set using a SYSIN2 DD statement in the job control language (JCL). You can specify the final order of the merged statements in columns 73 to 80 of the DFSDDLT0 control statements.
- Sending messages to the z/OS system console (with or without a reply).
6) How many ways application programs interact with IMS DB?
Application programs can interact with IMS DB in two ways:
- Applications that use the Data Language/Interface (DL/I) database call interface
- Java applications that use the IMS Universal drivers for Java Database Connectivity (JDBC) access or DL/I access
7) What is direct access IMSDB program?
direct access program accesses, for every input transaction, segments in one or more database records. These accesses are based on database record and segment identification. This identification is essentially derived from the transaction input and is normally the root-key value and additional (key) field values of dependent segments. For more complex transactions, segments can be accessed in several IMS databases concurrently.
8) What is sequential access IMSDB program?
A sequential access program accesses sequentially selected segments of all of a consecutive subset of a particular database. The sequence is usually determined by the key of the root segment. A sequential access program can also access other databases, but those accesses are direct, unless the root keys of both databases are the same.
9) What is the role of full function database?
IMS provides full-function database types to support direct and sequential access application programs
10) What is the role of fast path database?
Fast Path database types for direct access application programs
11) Is test PSB and production PSB are different?
YES, At execution time, each application program uses one PSB and it is usually a different PSB from those used by other application programs. At execution time, each application program uses a PSB that specifies the databases identified by the DB PCB it is authorized to process.