Base Columns, Column Display Objects, Output Columns and Variable Objects

For each base column defined in the Definer, the synchronization process automatically creates a visible interface element, typically, a text box. In addition, as a designer you can create non-database objects that also handle data, such as text boxes in dialogs.

To handle these elements, the Windows Designer uses two objects:

•A column display object that determines the look and feel of the column.

•An internal object called a Variable object for data-related properties such as data length and mandatory Y/N.

The use of Variable objects is fully automated. You only need to be aware of the Variable object type in a limited number of cases.

The characteristics handled by the Variable object type do not specifically relate to the graphical interface, but indirectly they influence default GUI look and feel.

If you open a column display control class from the Windows Designer catalog, you can only set its external appearance since the internal Variable class manages data-related characteristics. Once you have inserted the column into an info box or dialog, however, you can set or reset its base column properties.

If you set a base column control to non-displayed, look and feel properties no longer apply but the data-related information kept in the internal Variable object is made available by an output column object. The Object tree provides access to this object (child of the info box's query object). For displayed columns, the Design, Query Column menu option leads to the column display object. For non-displayed columns it leads to the output column object.

If you set a non-database data control to non-displayed, its data-related information is made available by a Variable object (there is no query with output columns). The Object tree provides access to this object.

The Object Browser tree view in the Object Activator tool lists base column objects under a "query" node, and non-database data objects under a "Variables" node.