CA IDMS Database Navigation

World®
’16
CA IDMS™ Database Navigation
John Siraco, Director, Software Engineering
CA Technologies
MFX72E
MAINFRAME AND WORKLOAD AUTOMATION

2 © 2016 CA. ALL RIGHTS RESERVED.@CAWORLD #CAWORLD
Abstract
The CA IDMS Database Navigation course focuses on the
characteristics of a CAIDMS database and the effects of
programming in that environment. You will learn how to
navigate through a network database environment using
data structures and currency rather than complex
programming syntax. You will also learn to how to use
navigational DML statements.
John Siraco
CA Technologies
Director, Software
Engineering

Agenda
INTRODUCTION TO CA IDMS/DB
DATA RELATIONSHIPS
CURRENCY
DATA STORAGE
SET STRUCTURES
DATA STRUCTURE DIAGRAM
1
2
3
4
5
6

Agenda continued
PREPARING FOR DATABASE ACCESS
VERIFYING DATABASE ACCESS RESULTS
RETRIEVING DATA
UPDATING DATA
PROTECTING DATA INTEGRITY
7
8
9
10
11

Introduction to CA IDMS/DB

Characteristics of CA IDMS/DB
§ CA IDMS is used for:
– Centralizing data
– Controlling the corporate information environment
– Managing Communications
– Developing applications

Centralizing Data

Controls and Documents
the Environment

Managing Communications

Developing Applications
§ Menu and syntax driven tools
§ Data Manipulation Language (DML)
§ Report generators
§ Fourth-generation (4GL) languages and development tools
§ SQL

Basic CA IDMS Terminology
Schema Logical
Definition
Subschema Logical
Definition
DMCL Physical
Definition
Complete description of
the database
Complete or partial
description of the
database
Restrictions
File description of the
database
Buffer definition
Journal definition
Source code only Source code and load
module
Source code and load
module
Not used at run time Used at run time Used at run time
Typically one per
database
Unlimited number per
database
Unlimited number per
database

Data Structure Diagram

Database Access Techniques
§ SQL
§ Navigational
– Data Manipulation Language – DML
§ Non-navigational
– Logical Record Facility - LRF

Data Relationships

Record Type and Record Occurrence
§ Employee Record
1234 John Doe 123 Oak Terrace Mad River OH 12345 6666
516-222-3232 0 012-34-5678
5253 June Moon 18 Balliol St Cambridge MA 02123 5555
617-222-2121 0 098-76-5432

SQL Terminology
Logical/physical
design
terminology
SQL
terminology
Non-SQL
terminology
Entity Table Record-type
Entity
Occurrence
Row Record
Occurrence
Data element Column Field element

Relationships Between Records

Implementing Relationships Between Records
§ Foreign keys
§ Sets

Implementing a One-To-One Relationship With a
Foreign Key

Implementing a One-To-Many Relationship With a
Foreign Key

Implementing a Many-To-Many Relationship With a
Foreign Key

Set Type and Set Occurrence

Implementing a Many-To-Many Relationship With Sets

Implementing a Many-To-Many Nested Relationship
With Sets

Data Storage

Data Storage Overview

Database Area Assignment

Database Page

Database Keys

Location Modes

Using a Unique Key as CALC Key

Using Nonunique Key as CALC Key

VIA Location Mode

Records Stored VIA in a Different Area

Records Stored DIRECT in an Area

Records Stored DIRECT Related by Set

Set Structures

Chained Sets

Indexed Sets
§ System-owned
§ User-owned

System-owned Indexed Set

User-owned Indexed Set

Chained Set Pointers

Chained Set Pointers (cont.)

System-owned Indexed Set Pointers

User-owned Indexed Set Pointers

Order Options

Set Membership Options

Connect Options

Disconnect Options

Data Structure Diagram

Record Components

Foreign Key Representation

Set Representation

Currency

How the DBMS Uses Currency to Walk a Set
5

How the DBMS Uses Currency to Sweep an Area

Categories of Currency
RUN UNIT 1002:3
RECORD
EMPLOYEE 1002:1
DEPARTMENT 4001:4
EXPERTISE 1002:3
.
.
.
SET
DEPT-EMPLOYEE
CURRENT 1002:1
NEXT 1000:1
PRIOR 1040:1
OWNER 4001:4
EMP-EXPERTISE
CURRENT 1002:3
NEXT 1002:5
PRIOR 1002:1
OWNER 1002:1
.
.
.
AREA
EMP-DEMO-REGION 1002:3
ORG-DEMO-REGION 4001:4
.
.
.

Tracking Currency Changes

Tracking Currency Changes (cont.)
JOB-EMPOSITION

How DML Verbs Use and Update Currency

How DML Verbs Use and Update Currency (cont.)

Preparing for Database Access

DBMS Requirements for Database Access

Host Language Program Requirements
§ Conversion of DML requests
– In the batch environment
§ COBOL
§ PL/I
§ Assembler
– In the online environment
§ COBOL
§ PL/I
§ Assembler
§ Run-time execution of the program

Converting DML Requests
§ Compiler-directive statements identify:
– The operating mode
– The subschema and schema names
– Record descriptions
§ Input to the DML Precompiler
– Host language program
– Information from the data dictionary
§ Output from the DML precompiler
– Error listing
– Host language program

Compiling a CA IDMS Program

DML Error Messages
§ I (Informational)
§ W (Warning)
§ E (Error)
§ F (Fatal)
§ T (Terminal)

COBOL Program Requirements for Database Access

COBOL Program Requirements for Database Access
(cont.)

Identifying the Operating Mode

Identifying the Subschema and Schema

Including Record Descriptions
Automatically

Including Record Descriptions Manually

IDMS Subschema Descriptions
SUBSCHEMA-DESCRIPTION
SUBSCHEMA-CONTROL
SUBSCHEMA-CTRL
SUBSCHEMA-NAMES
SUBSCHEMA-SSNAME
SUBSCHEMA-RECNAME
SUBSCHEMA-SETNAME
SUBSCHEMA-AREANAME
SUBSCHEMA-RECORDS

What is a Run Unit?

Bind Run-Unit

Identifying the Location of Records
in Variable Storage

Identifying Database Areas for Access

Area Usage Modes

Ending a Run Unit

Verifying Database Access Results

General Coding Considerations

IDMS Communications Block
(SUBSCHEMA-CTRL)
§ Program Variable Storage
§ 01 SUBSCHEMA-CTRL.
– 03 PROGRAM-NAME
– 03 ERROR-STATUS
– 03 DBKEY
– 03 RECORD-NAME
– 03 AREA-NAME
– 03 ERROR-SET
– 03 ERROR-RECORD
– 03 ERROR-AREA
– 03 IDBMSCOM-AREA
– 03 DIRECT-DBKEY
– 03 DATABASE-STATUS
– 03 RECORD-OCCUR
– 03 DML-SEQUENCE

Error-Status
Major
code
Minor
code
FIND/OBTAIN 03 26 Record not found
FIND/OBTAIN 03 07 End of set, area, or index
READY 09 66 Area not available for
requested usage mode
STORE 12 05 Storage would violate
duplicates not allowed (DN)

IDMS-STATUS (BATCH)

Steps Required With and Without AUTOSTATUS
§ With AUTOSTATUS
– Use “ON” clause in DML statement
– Include IDMS-STATUS in program
§ Without AUTOSTATUS
– Use “IF” test after DML statement
– Perform IDMS-STATUS after each DML statement
– Include IDMS-STATUS in program

Sample COBOL Code
Using AUTOSTATUS

Sample COBOL
Without Using AUTOSTATUS

Retrieving Data

Database Retrieval
§ FIND
§ GET
§ OBTAIN
§ RETURN

Database Retrieval Using OBTAIN

Database Retrieval Using RETURN

Entering the Database
AREA CALC
All Record Types CALC location mode
records
Physical Position Randomizing algorithm
First, last, or Nth of
particular record type or
all records in area
Symbolic key value for
record occurrence
INDEX DB-KEY
Record types within a
system-owned record
All record types
Symbolic key value for
record occurrence
Any database record
occurrence
First, last or Nth record in
index
Direct location mode or
previously accessed in
earlier run unit with DB-key
passed to run unit

Retrieving CALC Records
§ Retrieval by CALC key involves
– Field initialization: Move the CALC-key value to the
CALC-key field
– Currency used: None
– Common nonzero status codes: 0326 (DB-REC-
NOT-FOUND)

Performing an Area Sweep

Performing an Area Sweep
§ Currency used: Area
§ Common nonzero status codes: 0307
(DB-END-OF-SET)

Area Sweep

Retrieving Records in a Chained Set
§ Retrieval of members of a chained set
involves:
– Currency used: Current of set
– Currency updated:
§ After successful execution: All
§ On end-of-set condition: The owner becomes current

Ways to Walk a Set

End of Set Condition

IF EMPTY Test
MOVE IN-DEPT-ID TO DEPT-ID-0410.
OBTAIN CALC DEPARTMENT
ON DB-REC-NOT-FOUND
PERFORM DEPT-NOT-ON-DB
GO TO READ NEXT DEPT.
IF DEPT-EMPLOYEE EMPTY
PERFORM 900-NO-EMP-MSG
ELSE
PERFORM 350-DEPT-EMP-WALK THRU 350-EXIT
UNTIL SET-END-SW = “Y”
.
.
350-DEPT-EMP-WALK.
OBTAIN NEXT EMPLOYEE WITHIN DEPT-EMPLOYEE.
ON DB-END-OF-SET
MOVE “Y” TO SET-END-SW.

Accessing Multiple Member Sets
§ You can access occurrences of a single record
type:
– Currency used: Current of set
– Common nonzero status codes: 0307 (DB-END-OF-
SET)

§ You can access occurrences of all record
types

§ Currency used: Current of set
§ Common nonzero status codes: 0307
(DB-END-OF-SET)

Walking Multiple Member Sets

Owner Retrieval in Other Than Mandatory Automatic
Sets

Reestablishing Currency

Navigating Sorted Sets

Performing Generic Key Searches

Noncontiguous Sort Keys

Using RETURN to Establish Index Set Currency

Updating Data

Storing Records

Connecting a Record to a Set

Disconnecting a Record from a Set

Modifying Database Records

Erasing Database Records -
Basic ERASE

Variations of the ERASE Statement
§ ERASE PERMANENT
§ ERASE SELECTIVE
§ ERASE ALL

Qualified ERASE

Updating Data

Data Integrity Concerns

Central Version and Local Mode

Area Locks

Potential for Concurrent Update

Record Locks

Implicit Record Locks

Additional Implicit Exclusive Locks

Explicit Record Locks

Recovery From Program or System
Failure

Journals

Recommended Sessions
SESSION # TITLE DATE/TIME
MFX100S Strategy and Vision for CA IDMS 11/16/2016 at 12:45 pm
MFX101S Legacy is not a Dirty Word 11/16/2016 at 1:45 pm
MFX102S CA IDMS 19.0 Web Services for Modernization 11/16/2016 at 3:00 pm
MFX103S CA IDMS 19.0 SQL Enhancements for Modernization 11/16/2016 at 3:30 pm
MFX104S Java Access to CA-IDMS Data at BT (British Telecom) 11/16/2016 at 4:45 pm
MFX105S
Implementation and Use of Generic VTAM Resources
with Parallel SYSPLEX Features (CA and CAXIA)
11/17/2016 at 12:45 pm
MFX106S CA IDMS Buffer Tuning 11/17/2016 at 1:45 pm
MFX107S M3A Services Monitor, Measure, Manage and Alert 11/17/2016 at 3:00 pm
MFX108S Birds of a Feather/Stump the Techie! 11/17/2016 at 3:45 pm

Must See Demos
Demo Name
Product X
Theater # location
Demo Name
Services Y
Theater # location
Demo Name
Solution Y
Theater # location
Demo Name
Product X
Theater # location

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CA IDMS Database Navigation

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