i am doing data migration from DB1 to DB2. First step in that is extracting data from base tables(6 tables with one beig master table which has 1mil records and other 5 being detail tables) in DB1. This first step of extraction is done and data is uploaded in DB2.now it will take one month for all business validations and reconciliations to complete in DB2. Till this time, business has decided to keep DB1 up for it's users. Now the problem is , users can modifed or even create new records in all base tables during this one month. pls suggest me a good method to identify data which gets modified in DB1. Only mater table has timestamp field.Some of the detail tables doesn't have any timestamp field. It is not practical to run the extraction again. Please share any suggestions to identify specific record which got modified and run extraction script to validate and extract it.

I am doing data migration from DB1 to DB2.

First step in that is extracting data from base tables  (6 tables with one big master table which has one million records and other 5 being detail tables) in DB1.

This first step of extraction is done and data is uploaded in DB2. Now it will take one month for all business validations and reconciliations to complete in DB2.

Till this time, business has decided to keep DB1 up for it's users. Now the problem is , users can modifed or even create new records in all base tables during this one month.

Is there a good method to identify data which gets modified in DB1 during this time? Only the master table has a timestamp field, some of the detail tables don't have any timestamp field.

It is not practical to run the extraction again.

Please share any suggestions to identify the specific records which got modified, so one can run an extraction script to validate and extract it.