Support multiple column / field constraints for Postgres Reader and Writer

Please add multiple column/field constraint support also for MS SQL and Azure SQL database writers

Hello!

I talk about this feature with our Database development team. As you know, FME doesn’t support creating composite constraints for indices. The workaround is to use SQL to either:

1. Create the table with the desired constraints before writing
2. if you prefer, add them after writing, if you’re confident the written data will be compliant.

A good way to do this is to use SQL to Run Before Write on your writer, and then select Table Handle = Use Existing Existing Table in the writer feature type. If you need to use more than one SQL statement to do this, read the doc for FME_SQL_DELIMITER