FireDAC.Comp.DataSet.TFDAggregate
Delphi
TFDAggregate = class(TCollectionItem)
C++
class PASCALIMPLEMENTATION TFDAggregate : public System::Classes::TCollectionItem
Contents
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
| class | public | FireDAC.Comp.DataSet.pas FireDAC.Comp.DataSet.hpp |
FireDAC.Comp.DataSet | FireDAC.Comp.DataSet |
Description
TFDAggregate represents a maintained client aggregated value in a FireDAC dataset.
Use TFDAggregate to create and maintain a calculated client aggregated value.
TFDAggregate are collected into the TFDAggregates collection. The set of TFDAggregate may be created at design time as well as at run time.
The Expression property specifies the formula. GroupingLevel defines the set of records on which the value will be calculated. The value is calculated if Active and AggregatesActive are set to True.
If you want to display the aggregated value using data-aware controls, use TAggregateField instead of TFDAggregate.
Example
ADQuery1.AggregatesActive := True;
ADQuery1.Open;
with ADQuery1.Aggregates.Add do begin
Name := 'AvgSalary';
Expression := 'Avg(Salary)';
Active := True;
if InUse then
Label1.Caption := VarToStr(Value)
else
Label1.Caption := '<not accessible>';
end;