Add Computed Column
We can add a user-defined column through this item.
Example: Add a new column named AGE to base table emp.ctx by computing its BIRTHDAY column.
Select emp.ctx and click CTX -> Add Computed Column to open the following Add Computed Column interface:
Click Add button 
to add a computed column, and
set Expression and Alias. Then click Execute and you get
the following data in the composite table:
