Hi :
Database migration is to change one's database system for another one. This in most cases includes converting the existing data from their current format to the format employed by the new database architecture. There are many possible reasons why a company should consider migrating to relational database. Most important is that relational databases have the support of the majority of software manufacturers (most db products are written for relational databases, as they have become the standard in IT). Along the same lines, relational databases provide a faster way to deal with the most used data structures, as they use tables of records.
The most essential factors to consider when migrating to another architecture are data integrity (to avoid loss or invalidation of data), correct data structures in the new architecture (for example hierarchy trees in relational databases are not implemented by default) and support for existing functions and procedures.