Working with related tables and files > About lookups > Defining lookups
Defining lookups
1. Define the relationship for the lookup between the match field of the current table and the match field of the related table.
See Creating and changing relationships.
2. Choose File menu > Manage > Database.
3. In the Manage Database dialog box, click the Fields tab.
4. If your database contains more than one table, select the appropriate table from the Table list.
5. Select an existing text, number, date, time, timestamp, or container field from the list of existing fields, or define a new field.
6. Click Options (or double-click the field name).
7. In the Options for Field dialog box, click the Auto-Enter tab, then select Looked-up value.
8. In the Lookup for Field dialog box, choose the table the lookup will start with, and the table from which the value will be copied.
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.
9. Select the field from which the lookup value will be copied.
10. Select options for the lookup.
11. Click OK.
The relationship can sort the related records so that the first related record (the record the lookup will copy) is a particular record. For example, to look up the most recent checkout date for a particular piece of equipment, sort records in descending order by checkout date.
Be sure the lookup source field and lookup target field are the same field type; otherwise, you might get unexpected results.
When data in the related table changes and you want the current table to contain the new values, you can look up the data again. See Updating lookup values.
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
Defining automatic data entry