Class UserColumn

  extended by java.util.Observable
      extended by jimm.datavision.Expression
          extended by jimm.datavision.UserColumn
All Implemented Interfaces:
java.util.Observer, Draggable, Identity, Nameable, Selectable, Writeable

public class UserColumn
extends Expression
implements Selectable

A user column is an arbitrary expression inserted into the SQL query and retrieved as a column value. It may contain database column values, parameters, special values, strings, or numbers. It can't contain formulas because their values may be undefined when the query is run.

When used by a query, the following substitutions are made withing the userString of a user column: