Sunday, September 1, 2013

Database Migration Testing Appproach

Database migration testing is needed when you move data from the old database(s) to a new database. The old database is called the legacy database or the source database and the new database is called the target database or the destination database. Database migration may be done manually, but it is more common to use an automated ETL (Extract-Transform-Load) process to move the data. In addition to mapping the old data structure to the new one, the ETL tool may incorporate certain business-rules to increase the quality of data moved to the target database

1.All the live (not expired) entities e.g. customer records, order records are loaded into the target database. Each entity should be loaded just once.
2.Every attribute (present in the source database) of every entity (present in the source database) is loaded into the target database.
3.All data related to a particular entity is loaded in each relevant table in the target database.
4.Each required business rule is implemented correctly in the ETL tool.
5.The data migration process performs reasonably fast and without any major bottleneck.

Challenges that you may face in database migration testing include;
The data in the source database(s) changes during the test.
Some source data is corrupt.
The mappings between the tables/ fields of the source databases(s) and target database are changed by the database development/ migration team.
A part of the data is rejected by the target database.
Due to the slow database migration process or the large size of the source data, it takes a long time for the data to be migrated.

Testing Approach:
1. Set up the Test Environment.
2. Make sure Test Scripts are ready.
3. Make sure both Source and Target DB are ready.
4. How we do Data Migration mainly based on the TEST Scripts we have i.e Data Mapping Sheets  which contains the which data need to migrate to Target DB and how the DB should be migrated? is it a one to one mapping or multi to one field mapping or one to multi field mapping based on the given Transformation Rules.

5. And other thing we need to have good SQL knowledge mainly in JOINS.
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