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Integrated Database Management System (IDMS) Interview Questions and Answers


This page contains the collection of Integrated Database Management System (IDMS) Interview Questions and Answers / Frequently Asked Questions (FAQs) under category IBM (International Business Machines). These questions are collected from various resources like informative websites, forums, blogs, discussion boards including MSDN and Wikipedia. These listed questions can surely help in preparing for Integrated Database Management System (IDMS) interview or job.

What is IDMS?
IDMS = Integrated Database Management System
IDMS (Integrated Database Management System) is primarily a network (CODASYL) database management system for mainframes. It was first developed at B.F. Goodrich and later marketed by Cullinane Database Systems (renamed Cullinet in 1983). Since 1989 the product has been owned by Computer Associates (now CA Technologies), who renamed it Advantage CA-IDMS and later simply to CA IDMS.

Why would you use find and get rather than an obtain?
Find tells you whether the record is actually in the database. If it is not found you save the overhead of an obtain.

If the stored record is not defined as automatic of a set, how can it be stored as a member of the set?
Store the record then connect it to each set where it is a manual member.

Distinguish among erase, erase permanent, erase selective and erase all?
Erase cancels the membership of a record in specific set occurrences and removes only the named record.
Erase permanent removes the specific record and all mandatory occurrences it owns. It disconnects all optional members.
Erase selective removes the record, all mandatory members and all optional members not connected to other sets. It disconnects those that are connected.
Erase all removes the specified record and all the mandatory and optional records it owns.

So manual and automatic are the connect options for a set. What are the disconnect options?
Mandatory and optional.

What is currency in IDMS?
Currency is the location within the database during run-unit execution.
There are four levels of currency:
current of run-unit is the record occurrence of the last successful find or obtain;
current of record type is for the most recent of each record type;
current of record set is the most recent within each set and current of area is within each area.

What sets will the stored record connect to?
It will connect to all sets where it is defined as an automatic member. The store requires that currency be established for all these set occurrences.

How does IDMS insure data integrity?
IDMS uses record locks to prevent another run-unit from updating the same record.

What is an area sweep and when is it used in IDMS?
An area sweep accesses records on the basis of the physical location in a database area. It can be total, meaning a record by record search of the area, or it can be of occurrences of records of a specific type.

When you are obtaining next within a set and get a end of set return code, on what record are you now current in IDMS?
You are current on the owner.

What is a bind in IDMS?
A bind associates record types with the program work area; for run unit and records it is the first command issued in the program.

How does IDMS communicate with CICS?
They communicate via service MVS request calls.

Is there a application program coding difference between local and central version mode in IDMS?
No. The mode is specified via the SYSCTL DD card in the JCL.

If you are current on the owner of a set, what is the difference between an obtain next and obtain first in IDMS?
No difference. There is a difference between obtain first and obtain next for an area sweep, but not when current on the owner in a set.

What is the difference between a schema and a subschema in IDMS?
The schema is the physical arrangement of the data as it appears in the DBMS. The subschema is the logical view of the data as it appears to the application program.

What is a region in IDMS?
Region is used synonymously with area. It is a group of logically contiguous pages.

What is a page in IDMS?
A page is the smallest unit of storage in an IDMS database

Explain the difference between record occurrence and record type in IDMS?
A record occurrence is the instances of a record; it is the smallest addressable unit of data. A type is the description of a record; there needn't be any occurrences.

What is the difference between local and central version operating modes?
In local there is no IDMS System running above the DBMS. It's the more efficient mode but lacks the recovery and integrity facilities of the central version (CV) control program. In CV many application programs access the database through a single copy of the DBMS.

What is a run unit in IDMS?
A run-unit is a logical unit of work; it is analogous to a CICS task.

What is an OOK-Rec in IDMS?
An OOK-Rec is a one of a kind record set, used to get to another record set.

What is a junction record in IDMS?
A junction record is a member record type that allows for many-to-many relationship between its two owner records.

Name and explain the three location modes?
Calc is based on a symbolic value which is used to determine the target page. Via mode is for members only. Via records are stored near to their owners.
In direct mode the target is specified by the user and is stored as close as possible to that page.

What is a set in IDMS? What pointers are required, what are possible? How may sets be ordered?
A set is an owner record and, optionally, its member records. There are three types of pointers: next, prior and owner, but only next is required. There are five possible orders for arrangements of sets; they are: first - insert at beginning, last - insert at end of set, next - insert after current of set, prior - insert prior to current of set and sorted - insert according to sort value.

What is the purpose of a READY?
The READY prepares a database area for access by DML functions.

What does a COMMIT statement do?
It writes a checkpoint to the Journal File and releases any record locks.

What does a ROLLBACK do in IDMS?
It rolls back (reverses) all database updates to the point of the last rollback or to the beginning of the run-unit.

What does a FINISH do in IDMS?
It releases all database resources, terminates database processes, writes statistical information to IDMS and logs the checkpoint.

What is the IDD in IDMS?
IDD is the Integrated Data Dictionary. It contains information about the elements, record types, sets, maps and dialogues within the database.

What is the meaning of the return codes 0307 and 0326?
0307 is end-of-set and 0326 is record not found.

What is the meaning of Copy IDMS Subschema-Binds?
It generates a bind run-unit and binds all the records for the sub-schema the program is referencing.

What is the meaning of Copy IDMS Subschema-Binds in IDMS?
It generates a bind run-unit and binds all the records for the sub-schema the program is referencing.

What is autostatus in IDMS?
Autostatus is a protocol mode which causes the expansion of each DML statement to include a 'perform IDMS-Status' statement.

What does a store statement do?
It places a record in the database based on the location mode specified.

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