Restore constraints on masked tables
Since the nature of some masking operations may render the data inconsistent with respect to the unmasked tables, currently all constraints and indexes are removed from the masked tables before the population INSERTs. This is not desired, as it may impede data usage after masking. Constraint restoring strategies to be considered:
- Remove NOT NULL constraints only if the operation can render the values NULL.
- Use functions described in https://www.postgresql.org/docs/current/static/functions-info.html to get the constraint DDL.