We had a client who wanted to consolidate two very large systems which were originally two separate implementations of the same web application. As part of this consolidation effort data from one database had to be merged into the other and this process was complicated by the fact that some users had information in both systems.

The project included some database design to normalize critical data, merge millions of records from numerous tables, and then consolidate duplicate user accounts that previously existed within one or the other of the two databases.