Partial db dump/restore

A part of my database (PostgreSQL 9.3) relies on extra tables (ex. County, City, Town, ... ). I don't manage these tables, they are updated regularly by a third party. Each time I get a new full dump, but I have a hard time to push the changes back into my DB.

I've played with pg_dump / restore and run into some constraint issues duplicate key value violates unique constraint or cannot drop constraint ... because other objects depend on it even with --disable-triggers or --clean option.

Is there an option I've missed? I've found there are some ways to turn constraint on/off but I've no idea if it's the good way to solve this or just a dirty hack? (I'm not a DBA expert.) To be honest, I'm quite surprised there isn't an easy way to achieve this. Maybe I've missed it! I naively thought I could run pg_restore as a big transaction and check constraints at the end of the script. Is it possible?

How about trying to solve this problem with Point-In-Time-Recovery? A dump has the problem that you got an old set of data anyway. I highly suggest to use a backup method giving you ways more recent version of the data.

You can also write yourself a simple change-log trigger storing all the information which has changed in a simple table. Here is how it works: http://www.cybertec.at/tracking-changes-in-postgresql/
The code in the site should give you a rough prototype and help you to fix things.

StackExchange Database Administrators Q#81097, answer score: 3