Oracle database migration from 11g to 12c

Question

I need to do a database migration from Oracle 11g to 12c. But I cannot do a direct export and import kind of a migration since there are a lot of schema changes which are going to happen. I already have the column mappings in a sparedsheet with old columns and new columns with all details such as data type, constraints, etc. There are new columns added to many tables are the default values that should be populated are also known. So what should be the best approach to do this migration?

Answer 1

There are more ways to do this. Start with getting a dba involved.

To minimize production downtime, you could check if making a logical standby database is feasible in your situation. In that case, make the target database a 12c one, that saves for upgrade time.This target database is in sync with the source database at all times and makes it very valuable. Clone the target database and use that clone to test the migration steps. If the migration fails, you can easily re create a new clone to correct the migration process on.

Working in this way could even enable bi-directional replication, replication from the migrated database back to the source database that could make it possible to revert to the original database in the unlikely event that after production start on the new database things don't work as expected.

Start with adding a dba to the project, a good dba can help minimize downtime and reduce risk.