Multiple columns

The multiple columns enable to centralize in one class objects of various types and define columns in the class, meaning of which will depend on a value in another column. We will create e.g. class Means of transport and define a column Type and multiple columns Text1, Text2 and Text3. Column Type can keep value Ship, Car or Plane. Depending on this value columns Text1, Text2 a Text3 are marked Displacement, Number of propellers, Number of funnels or Power, Number of cylinders, Number of seats or Range of flight, Number of engines, Number of passengers.

It is an alternative of an approach based on creation of several special classes that inherite from their parent class attribute Type. It is a simple although less conceptional solution (in terms of data integrity) that can be used effectively in certain situations.

Multiple columns have to be enabled in the class definition and the control column has to be selected. The control column has to be reference to another class. Based on the value in the control column selected columns are named for the particular record. After saving and opening the class definition again there will by available icon Multiple columns that leads to the page for multiple class selection and defining their names for particular records from the class to which the control column refers.

Examples for achieving high data integrity are described here here.