Your fact tables are organized by concept: e.g. all diagnoses facts are in one table; all medication facts in another
The process of setting up the i2b2 to use multiple fact tables is straight forward. Once you have updated your software to at least version 1.7.09, created your new fact tables and loaded the data into them there are only two remaining steps.
Update the terms in your metadata tables so the i2b2 server knows what fact table to query
Turn the Multi-fact table feature on in the crc.properties file