Hi all,

I have a requirement to extract and migrate additional fields of data from legacy non-relational database system into the re-engineered relational database based application.

Main requirement:

1) To be able to accommodate the ever changing requirements for data from different clients; thus need a process to persist the newly required data that will avoid downtime of the system and has minimal effect system performance during client data retrival requests.

Some of the options we have are as follows but not sure which is better over the other:

2) Migrating data using the application to persist the data into the relational database.
3) Migrating data direclty into the relational database.

In this regard, are there any industry standards in place as this is a common issue in many enterprise applications.

Any help in this regard is highly appreciated.

Thanks in advance for your time and interest.

The legacy system has to be taken offline when RDBMS application is brought online.
Otherwise you can never turn off legacy, because you have no tested RDBMS based application.
Also, it is folly to have data entry into both system concurrently due to many data entry errors making automated comparison infeasible.