Task: Perform Data Migration
This task focuses on performing the data migration.
Disciplines: Development
Purpose
  • To extract, transform, migrate, validate, and verify data has been correctly migrated based on the Data Migration Specification
Relationships
RolesPrimary Performer: Additional Performers:
InputsMandatory:
    Optional:
      Outputs
        Steps
        Extract, Transform, and Migrate Source Data to Target Data

        Using the Data Migration Specification, Test Plan, and Test Strategy as your guide:

        • Extract source data
        • Transform source data
        • Migrate transformed data

        To successfully perform this step, the implementer needs to work with a business designer possessing an intimate knowledge of the data that needs to be migrated and a business analyst with knowledge of both the source and target system data.

        Ideally, the completion of data migration should immediately precede the start of production running of the system. However, when the data is very volatile or very large or when the validation of the migration results is a lengthy process, amendments to the migrated data might be necessary. This is especially true where manual data has to be collected, verified, and then entered to the automated system; in these circumstances, data capture might take many months.

        In such cases, you need to plan and define the maintenance procedures to keep the migrated data up-to-date in any interim period between the completion of the data migration and the initiation of production running. These procedures need to strike a balance between economy (they will not normally be in use for very long) and accuracy (they must not introduce errors into the converted data). They should also incorporate controls and audit trails as applicable.

        Whenever possible, entry of manually converted data should be performed using the standard data entry processes of the new system. Occasionally, specially built conversion processes are unavoidable. A typical example is the bulk batch entry of data which would normally be entered interactively, but where volumes are too high to make interactive entry practical. The manually migrated data can be identified in the Data Mapping Table contained in the Data Migration Specification.

        Validate and Verify Source Data and Target Data

        After extracting, transforming and migrating data, as specified in the Data Migration Specification, you need to validate and verify the resulting data. A summary analysis of the results of the data migration will be captured in the Data Migration Evaluation Summary.

        Validation and verification is a critical step. Improperly converted data can lie dormant and cause invalid results in the new system and, often worse, invalid results that remain undetected. Careful validation is needed to prevent this time bomb effect. The risk is often heightened because of the volume of much of the data and because the project team might have only indirect control of the migration process.

        As with all testing tasks, you should first define the test strategy that you will use to validate and verify the migrated data. In addition to what is described in Define Test Approach, the following considerations should be taken into account:

        • Data accuracy
        • Testing of Automated Data Migration
        • Control procedures