When replacing an old business application with a newer one, simply installing new application is not sufficient. Instead, the data stored in the old application must be migrated into the new one. The following papers (some of them are joined work together with Ch. Schulz) might be helpful in case you work in the same area.
Data Migration Project Management and Standard Software – Experiences in Avaloq Implementation Projects provides a good overview how data migration projects work. The focus is on data migration as part of an integration project with complex standard software. The example is about a core-banking system, but the same principles apply to other systems such as SAP as well.
Towards the Industrialization of Data Migration: Concepts and Patterns for Standard Software Implementation Projects has a technical perspective. The target audience are developers new to data migration. It sketches various implementation concepts and typical implementation patterns. They are useful no matter whether the coding takes place in SQL scripts or in ETL tools.
Testing & Quality Assurance in Data Migration Projects looks how to ensure a proper data migration. This is often a critical aspect. If a bank loses some customers during a data migration or confuses the account balances of customers, they have at least a reputational problem. However, classical functional testing is not really appropriate for validating the correctness of data migration scripts and does not cover operational risks associated with data migrations – exactly these challenges are discussed in the paper.
A detailed process model for large scale data migration Projects discusses the various phases in a larger data migration project. Its particular strength is that it founds on the input of a large number of professionals from various companies and industry sectors.
For those understanding German, the article Datenmigration bei Standardsoftware-Einführungsprojekten might be of interest as well. It has a mixed technical and organizational perspective on data migrations.