The first three parts of this article described the design of the new database and the migration of data. This last part describes how the applications will be modified to allow them to access the new database instead of the old IMS database.
This program adaptation must meet two constraints :
In our previous article, we had briefly described the principles of migrating an IMS database towards a relational database (SQL). In this new article, we are going to describe how the structure of the legacy database can be reverse engineered and how the new database can be designed.
The data migration is broken down into three phases :