Can you explain what is meant by a custom format when creating a database dump?

The custom format when creating a database dump is a format that differs from the standard text SQL dump. It is usually binary and allows storing the database data and structure in a more compact and convenient form for restoration.

For example, in PostgreSQL, when using the pg_dump utility, you can specify the dump format as "custom" (-F c). Such a dump:

• Allows selective restoration of individual tables or objects
• Supports data compression
• Restores faster

This is useful when you need flexible management of backups and restoration, rather than just having a text script with SQL commands.