Kbase 14202: How to preserve data during schema update in Roundtable
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
10/05/1998 |
|
How to preserve data during schema update in Roundtable
DRAFT COPY - Currently under review and edit.
INTRODUCTION:
=============
Roundtable allows you to make schema changes that could cause loss of
data. When the UPDATA SCHEMA process is run to apply the change, a
status of DELETE signifies that data could be lost.
WHY YOU NEED TO KNOW THIS:
===========================
When data is going to be lost, Roundtable has a data preservation
or TRANSFORMATION process that can be accessed from the Update Schema
process, or the Build Schema process in deployment.
PROCEDURAL APPROACH:
====================
When a schema update table yields a status of Delete, data
preservation can occur. To do this you must change the action of the
Updatea schema to TRANSFORM.
Roundtable generates some sample dump and load programs that need to
be customized. Customize these by editing the DUMP and LOAD programs.
The dump program should be reviewed for accuracy. The load program
most everytime needs to be modified, because Roundtable can't estimate
where this lost data would need to go.
When the Update Shema process is run Roundtable runs the DUMP program,
applies the schema change, and then runs the LOAD program. If an
error occurs during the dump and load process the Update schema
will halt and wait for the problem to be resolved before continuing.
REFERENCES TO WRITTEN DOCUMENTATION:
====================================
Progress Software Technical Support Note # 14202