Field and Record Size Expansion
Objectives
The goal of field and record size expansion is to eliminate field or record
size mismatches or to change the capacity of all occurrences of a logical
element. The first issue addresses system reliability. The second issue is
typically related to an external requirement such as growth of the customer
base, regulatory changes (zip code) or century date change.
This is a difficult task to perform on older systems because redundancy and
poor naming conventions do not lend themselves to data element tracing. The
process outlined below follows a model similar to data name rationalization.
Implementing data name rationalization and field and record size expansion
concurrently is a matter of merging the two tasks. The benefit of doing this is
that a joint project can be completed more efficiently than performing these as
separate tasks. Specific objectives for field and record size expansion include:
· Correcting mismatches among related field and/or record groups
· Expanding records to include additional fields
· Standardizing date routines across the application systems
· Expanding fields, records and related system components to conform
to some new user requirement
Note: Task steps that identify and consolidate shared record groups impacted
by a size change, and trace secondary program level data elements, utilize
automated tracing reports. Attempts to employ manual methods have seen limited
success.
Entrance Criteria
The entrance criteria for the field and record size expansion task are listed
below.
· A requirement for specific field and record types to be expanded
· Completion of the data definition analysis of the technical
assessment component of the Inventory/Analysis stage including:
- Field size expansion analysis
- Physical data analysis
· Completion of the environmental analysis task
· Determination of the field/records to be expanded
· Completion of the application staging task for system components as
listed input requirements below
Roles/Skills
The personnel and skill requirements necessary to meet the field and record
size expansion task objectives are identified below.
· Data Definition Analyst
- Knowledge of application data structure and content, and expertise
in applying data manipulation tools and techniques
· Current Systems Expert
- Knowledge of existing system source operational requirements and
application functionality
· Redevelopment Expert
- Ability to update application area in respect to stated
corporate standards
- Knowledge of tools and coding techniques to produce and enhance
redevelopment goals
Input Requirements
The system components and related inputs required to initiate and complete
the field and record size expansion task are listed below.
· System components including program, Copy, JOB, DDL and screen
definition source loaded into Original/Input working libraries
· Identification of fields and/or files of interest to be expanded
Note: This could be all record groups across the systems of interest.
· Data definition standardization (DNR) control log Form 023
· Positioning work plan Form 020
· Record grouping reports created in the data definition analysis task
· Primary, or representative, I/O record definitions identified during
data definition analysis
· Field expansion analysis metrics created during data definition analysis
· Inventory lists and cross reference reports created in the environmental
analysis, and possibly updated during data definition analysis, including:
- Screen cross references
- DDL cross references
- File cross references
· Data definition analysis results recorded on Form 003C
Tool/Technology Support
Technologies supporting the field and record size expansion task include date
field expansion tool, date impact analyzer, interactive date change facility,
year 2000 date routines, open systems repository, cataloging tool, program
editor, spreadsheet and word processing tools. These tools are used to represent
information as required by this task.
Date field expansion tool
Field expansion projects require expansion of existing fields on files, data
bases, and within programs. Expansion of fields requires converting record
groups and program fields. The main role this tool plays within this task is to
identify, automatically convert and document changes in programs, record groups
and, in some cases, control objects throughout system.
Date impact analyzer
It is nearly impossible to perform large scale date impact analysis without
automated tools. In an IBM MVS or similar mainframe environment, identifying all
potential date related records/fields is very time consuming. The main role this
tool plays within this task is to rapidly and automatically identify how dates
are used by programs and to provide a complete cross-reference of those
components affected by a change - including source code, copybooks, files, JCL,
CICS tables, etc.
Requirements include identifying date usage in programs (i.e. MOVEs, COMPAREs),
element tracing throughout an application, support for COBOL 88 levels and
Redefines and identifying indirect date references, synonyms and missing or
obsolete components. Date impact analyzer tools should provide a set of default
date search criteria that can be modified and expanded depending on company
standards.
As with most of the tools discussed in the Positioning stage, strong support
is limited to COBOL. Tracing facilities to support PL/I do exist, but are not
specifically geared to field expansion.
Open systems repository
A repository provides an important, yet optional, capability to link data
definitions to other definitions and to physical objects using a formal model.
Use of repository in this task requires that system-wide meta-data was
established during environmental analysis and data definition analysis. For
large systems or cross functional expansion efforts, this repository model can
be maintained as a sophisticated mechanism for managing project efforts.
Requirements include the ability to reflect system components as objects
within the repository model and populate that model from a legacy environment. A
recommended transition meta-model that supports this analysis is shown in the
Appendix section of the Comsys-TIM product. A secondary, and optional,
requirement involves accepting an automated load format based on tools that
parse and analyze legacy environments. One suggested subset of the LTM is shown
in the figure below.
Cataloging tool
This is required to establish several libraries with which to manage the
expansion of the fields in the source. Any library management tool should be
able to accomplish this.
Program editor
This is required to physically expand the records, composites, and related
statements in the source. Use a program editor appropriate to the environment.
Spreadsheet
Spreadsheet tools offer a convenient format for recording much of the
information gathered throughout this stage. Referenced Comsys-TIM Forms have
been pre-loaded into certain spread sheet tools (see the step level tool
guidelines for specific tools) to facilitate data entry and analysis. While
highly desirable, spreadsheets are not essential to this task.
Word processor
This is required to record positioning narrative and, in the absence of a
spreadsheet tool, other positioning results.
Task Steps
The field and record size expansion task is comprised of the following task steps:
