Defining lookups
Important  Before you begin, be sure you understand how lookups differ from relational databases. See About lookups.
To define a lookup:
Define the relationship for the lookup between the match field of the current table and the match field of the related table.
See Creating relationships.
With the database open, choose File menu > Manage > Database.
In the Manage Database dialog box, click the Fields tab.
Click Options (or double-click the field name).
In the Options for Field dialog box, click the Auto-Enter tab, then select Looked-up value.
For Starting with table, choose the table that the lookup will use as its starting point in the relationships graph.
For Lookup from related table choose the related table from which the related data will be looked up.
For If no exact match, then, select an option to copy no value, copy the next lower or next higher value that's in the lookup source field, or enter a fixed value to be used instead.
Select Don't copy contents if empty. (Clear this option to allow empty data to be copied.)
Notes about defining lookups
Be sure the lookup source field and lookup target field are the same field type, otherwise you might get unexpected results.
To change a lookup, be sure Looked-up value is selected in the Auto-Enter options, click Specify, then make your changes.
To stop or suspend using a lookup, clear Looked-up value in the Auto-Enter options.
Important  When a lookup is based on a multi-criteria relationship, a lookup will be triggered each time a value is entered into any of the fields that are involved in the multi-criteria relationship. The lookup is being performed each time a value is entered into one of the required fields. When all of the requisite fields have values, the final lookup value will be copied into the lookup target field.
Related topics 
About lookups
About relationships
Updating lookup values
Defining automatic data entry