TAggregateField = class(TField)
class PASCALIMPLEMENTATION TAggregateField : public TField
TAggregate field represents a maintained aggregate in a client dataset.
TAggregateField represents an aggregate value from a client dataset in a form that can be used by data-aware controls. Use the Fields editor on a ClientDataSet to create a persistent aggregate field to which a TDBText control can bind.
As with TAggregate, TAggregateField has an Expression property that represents a calculation summarizing the data in a set of records. When using aggregate fields, you do not need to explicitly create the corresponding aggregate object in the client dataset: the Fields editor creates that object when you create a persistent aggregate field.