Most applications do not explicitly create instances of TFloatField. Instead, the field components are created automatically, as persistent field components defined in the Fields editor at design time or as dynamic field components created automatically by the dataset. 

Create sets the DataType property to ftFloat and Precision to 15. The AOwner parameter specifies the component, typically a dataset, that becomes the new field's Owner. The Owner is responsible for freeing the component. 

In the rare cases when you must create a persistent field component at runtime, call Create to create and initialize an instance of TFloatField. After instantiating a TFloatField, associate it with a specific field by setting its FieldName property to the name of the field. Give the TFloatField a unique identifier in the Name property. Establish where the field appears in the collection of fields by providing an ordinal number in the Index property. Associate the TFloatField with a dataset component by setting its DataSet property to the name of the dataset component. Optionally set the Precision property to the desired degree of precision. 

The example below creates a TFloatField object for a field named Amount accessed through a TSQLDataSet named SQLDataSet1.

var
  T: TFloatField;
begin
  SQLDataSet1.Close;
  T := TFloatField.Create(SQLDataSet1);
  T.Precision := 2;
  T.FieldName := 'Amount';
  T.Name := SQLDataSet1.Name + T.FieldName;
  T.Index := SQLDataSet1.FieldCount;
  T.DataSet := SQLDataSet1;
  SQLDataSet1.FieldDefs.UpDate;
  SQLDataSet1.Open;
end;

SQLDataSet1->Close();
TFloatField *T = new TFloatField(SQLDataSet1);
T->Precision = 2;
T->FieldName = "Amount";
T->Name = SQLDataSet1->Name + T->FieldName;
T->Index = SQLDataSet1->FieldCount;
T->DataSet = SQLDataSet1;
SQLDataSet1->FieldDefs->UpDate();
SQLDataSet1->Open();

Destroy 

Create 

DataType 

Precision 

Owner