Working with related tables and files
FileMaker Pro uses related tables as the basis for relational databases and lookups. Relational databases allow you to work with data from other tables dynamically, so that you can change data in one place and your changes are reflected in all places where the related data appears.
Use relational databases to:
See and work with data from another (or the current) table in its most up-to-date state. For example, you can display data in related fields when you need current data from a related table, such as the current price of an item.
Set up and manage data efficiently and with flexibility. Instead of creating many database tables or files with duplicate values, you store single occurrences of values and use relationships to make those values available. You can then make changes to data in only one place, which eliminates data duplication and promotes data accuracy.
For information about creating relationships, see Creating relationships.
Lookups let you copy data from one table to another; once looked-up data has been inserted, it does not change unless you edit it or tell FileMaker Pro to look it up again.
Use lookups to:
Related topics 
About planning a database
Adding tables to the relationships graph
Creating relationships
Topics in this section
About relationships
About the types of relationships
Working with the relationships graph
Summarizing data in portals
Filtering records in portals
About lookups