Advanced Data Connector (ADC)
ADC takes a different approach to data access. ADC is very efficient in dealing with large datasets because it gives you control of the queries. This allows you to optimize queries for performance. With ADC you can access multiple databases from your rules, for example reading from one database and writing to another. With EDC, you're limited to one database.
Both read and write performance are much better than EDC when processing larger datasets. ADC can read related data in a few passes from the database, where EDC performs discrete queries to fetch data. And ADC can write back data in chunks, where EDC writes data as discrete updates.