1⟩ Explain IMS Software Environment?
IMS Software Environment consists of the below five main components:
► IMS DB
► DL/I
► DL/I Control Blocks
► IMS DC
► Application Programs
IMS DB
Home Mainframes IMS DB
“IBM Information Management System (IMS) is a joint hierarchical database and information management system with extensive transaction processing capabilities.”
39 IMS DB Questions And Answers
2⟩ What is DL/I?
DL/I is a command-level language to manipulate IMS databases. DL/I forms a bridge between application program and IMS database. It is used in batch and online programs to access data stored in IMS databases.
Every access to an IMS database is through DL/I. The DL/I interface must be called to update or read a IMS database. DL/I allows both sequential and random processing of a database.
3⟩ What are the advantages and disadvantages of a Hierarchical Database?
Advantages:
► Speed of access is faster because of the predefined data paths.
Disadvantages:
► Complex implementation
► Predefined tree structure reduces flexibility.
► Difficult to manage
4⟩ What do you mean by Hierarchical Database?
► Follows inverted tree structure
► Data relationship is predefined by it's structure
► Program accesses the data through predefined paths.
5⟩ What are the objectives of DBMS in IMS?
► Increases data independence
► Reduces data redundancy
► Provides data communication facilities
► Reduces data maintenance
► Provides data integrity and security
► Provides indexing capabilities
6⟩ What is DBMS in IMS?
A Database Management System is used to define and maintain the structure of the database.
7⟩ What is IMS (DB/DC)?
IMS (Information Management System) is IBM’s hierarchical database management system. It has mainly two components: IMS DB and IMS DC (also know as IMS TM)
IMS DB - IMS/Database Manager as the name implies manages the IMS databases. It is used for physical storage creation and management and data retrieval.
IMS DC / IMS TM - IMS/Data Communications or IMS/Transaction Manager handles online transaction processing system.
8⟩ What is an IMS Database?
A Database is a collection of related data items organized in a way that can be processed by application programs.
9⟩ What are the path calls in imsdb?
Path call retrieve all the segment occurrence present for an particular DB or root segment
10⟩ What is the maximum number of PCBs allowed in a PSB?
Any number more than 1 (no limitation)
11⟩ What is the maximum of key fields and search fields allowed in a segment?
Key fields - Only 1
Search fields - No limitation
12⟩ What are the two ways in which DL/I interface can be invoked?
► By making a call to IBM supplied program CBLTDLI / ASMTDLI / PLITDLI
(most commonly used method) by - Passing a PCB, or Passing an AIB
► By invoking the EXEC-DLI CICS interface by Passing a PCB, or Passing an AIB
13⟩ What is the maximum number of fields allowed per segment and what is the maximum number of fields per database?
Max. number of fields per segment = 255
Max. number of fields per database = 1000
14⟩ Portfolio analysis application is an example of?
15⟩ How many root segments do we have per database record?
Only 1
16⟩ What is the maximum number of segment types allowed for a single database?
255 Segment types
17⟩ What is the maximum number of levels allowed in IMS DB?
15 Levels
18⟩ What are the retrieval sequences in IMS DB?
► Top to Bottom
► Front to Back
► Left to Right
19⟩ Can we use PROCOPT on PCB and Segment field (SENSEG)?
Yes, we can use the PROCOPT on PCB macro (at database level) or sensitive segment macro (at segment level).
20⟩ What is meant by BMP mode?
It is of two types:
Transaction oriented
► Can read and write to online message queues.
► Can process online files and databases.
Batch oriented
► Can only read message queues.
► Access online databases in Batch mode
