When you define drilldown substitutions on a table object, only those variables selected as the display variables in the table's data attachment are available for setting substitution values. In the previous example, if the Velocity variable was not selected as a display variable for the table, then it would not have been available as a column in the Drill Down Column Substitutions dialog.

If you have a DataView field that you want to use to set a substitution when performing a drilldown on a table but do not want to appear as a column in the table, include it as a display variable when defining the attachment and set the columnsToHide property to prevent it from being displayed. To hide multiple variables specify them as a semicolon-separated list.

The columnsToHide property is preset to hide the apama.instanceId column. Apama transparently forces apama.instanceId to be included as a display variable on all table objects. This is so that you perform a drilldown, $instanceId can be set to the ID of the selected instance. You should always hide the apama.instanceId column.