FAQ: What is the difference between a RELATE and JOINITEM?
What is the difference between a RELATE and JOINITEM?
JOINITEM takes two themes and creates a third theme that is a combination of both themes. Typically, JOINITEM is used for joining a record theme and a feature theme (point, line, or polygon). In this case, the feature theme is always the input theme and the output theme and record is the join theme.
If there is a duplicate item in both the input and join theme, only one copy is saved to the output theme.
RELATE temporarily links two themes based on an item value that occurs in both files. RELATE is similar to JOINITEM, except that the items in the related theme is not added to the input theme from theme. Rather, they are temporarily accessed when using the input theme.
Only two themes can be related at one time. A RELATE is only valid in the session in which it is created. RELATE is used a lot when you have multiple departments with sensitive data that cannot be shared with everyone. This allows multiple users the access to the same features and different relational databases.
DDRELATE can be used to specify the information in a dialog box rather than the command line.