Migration and Conversion Overview

The objective of a migration and conversion project is to extract data from one system and use it to populate the database of another system. Migration projects generally require that a significant amount of data cleanup and transformation work be performed before the extracted data is loaded into the new system.

Typical project plan

The typical project consists of three major phases: design, development/ test, and cutover. For those customers that have "easy" jobs to do, remember that each of these stages can take a few hours or a few weeks to do, depending upon the complexity and scale of the project.

Stage 1: Design

The design stage is devoted to obtaining, organizing, and documenting the following information:

The source of the data. What table, file, field, and field position is each transferred data element coming from

The transformations, edits, and tests that must be done prior to target-system load. This includes formulas or algorithms for converting data from one form or value to another, edit checks to make sure data values fall within the allowable range as required for the new system, and any tests that are required to meet data integrity, uniqueness, and referential integrity constraints imposed by the target system

The destination of the data. What location within the target system's data store will the each element be stored into once the transformations are completed successfully.

The Cutover Test Plan. What final acceptance tests will the customer and Redbridge perform to assure us that the tranfer of the data is done accurately and completely?

Design Stage Collaboration

The customer supplies all available documentation about the source, transformations and destination of the data. This information is usually readily available, but in rare cases it must be laboriously reconstructed, often by trial and error. Once this information has been obtained, Redbridge consolidates all this material into a mapping document that spells out where each data element is coming from, where it's going, and any applicable transformations, edits, and tests that must be performed on the data prior to being loaded into the target system.

The customer then reviews the mapping document, signs off on it, and that kicks off the development and testing work.

Stage 2: Development and Test

Redbridge uses the mapping information from the Desigh phase as blueprints to write all the required programs to extract the data from the old system, clean and transform the data, and load it into the new system. As the coding is completed for each section of the data to be transferred, it is unit tested. Once all unit development and testing is done, a full system-test is performed. This testing and development is typically done as an iterative, incremental process until finally the entire system can be run, front to back with one press of a button. Then we're ready for cutover.

Stage 3: Cutover

Once the transfer software is built and tested, it's time to run it one last time against the latest-and-greatest production data. The work in this phase is mainly to coordinate the final run with everyone, and do a post-transfer go / no-go spot-check to make sure everything worked as expected. If all's well, the old system can be retired.