Three Kinds of Fields

There are three kinds of fields in True DataControl:

Data fields	Data fields are actually stored in a database (data source mode) or in internal storage (memory array mode). In data source mode, if no fields have been defined, True DataControl retrieves fields from the data source, automatically creating a data field for each field in the data source. In memory array mode, you create your own data fields, thus defining the structure of the underlying array. In user events mode, you are also required to define data fields manually.
Calculated fields	Calculated fields are not stored in the database, they are evaluated as needed by True DataControl. The value of a calculated field is determined by evaluating an expression, or in CalcFields event. Typically, the expression depends on the value(s) of other field(s). In True DataControl Lite, calculated fields are only accessible to True DBGrid 8.0 directly bound to TDataLite.
Linked fields	Linked fields are used only to establish a one-to-one link between a dependent TData control and its master, in which case the linked field (defined in the master) represents a data field in a dependent TData control. Linked fields are unavailable in True DataControl Lite.

At design time, the FieldKind property value is determined according to which of the three option buttons is selected: Data, Calculated or Linked.

If you create a field in code at run time, you must set its FieldKind property to indicate one of the three groups to which the field belongs.