User manual

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Chapter 4 | Working with related tables and files 85
About relationships
A relationship is a powerful method for organizing your data. Using a relationship, you can join
data in one or more tables based on common field values, different field values, or a comparison
of values in two or more fields.
After you create a relationship, you can do either of the following to display the data from the
related table:
1 Design a relational database, which is one or more tables that, when used together, contain all
the data you need for your work. Each occurrence of data is stored in only one table at a time,
but can be accessed and displayed from any related table. You can change any occurrence of
your related data, and the changes appear in all places where that related data is used.
1 Define a lookup to copy data from a related table into a field in the target table. The copied data
is now stored in two places, just as if it were copied and pasted into a target field. Looked up
data is current at the time it is copied, but once copied it remains static unless it is re-looked up
or the lookup is triggered again.
12Customer ID
TangLast Name
12Customer ID
TangLast Name
12Customer ID
TangLast Name
Lookups copy data from the related table into the current table
In relational databases, data from the related table is only
displayed in the current table, not copied
12Customer ID
TangLast Name
Current table Related table
Current table Related table