Most applications do not explicitly create instances of TSmallintField. 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 ftSmallInt, MinValue to -32768, and MaxValue to 32767. 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 TSmallintField. After instantiating a TSmallintField, associate it with a specific field by setting its FieldName property to the name of the field. Give the TSmallintField 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 TSmallintField with a dataset component by setting its DataSet property. 

The example below creates a TSmallintField object for a field named Children accessed through a TSQLDataSet named SQLDataSet1.

var
  T: TSmallintField;
begin
  SQLDataSet1.Close;
  T := TSmallintField.Create(SQLDataSet1);
  T.FieldName := 'Children';
  T.Name := SQLDataSet1.Name + T.FieldName;
  T.Index := SQLDataSet1.FieldCount;
  T.DataSet := SQLDataSet1;
  SQLDataSet1.FieldDefs.UpDate;
  SQLDataSet1.Open;
end;

SQLDataSet1->Close();
TSmallintField *T = new TSmallintField(SQLDataSet1);
T->FieldName = "Children";
T->Name = SQLDataSet1->Name + T->FieldName;
T->Index = SQLDataSet1->FieldCount;
T->DataSet = SQLDataSet1;
SQLDataSet1->FieldDefs->UpDate();
SQLDataSet1->Open();

DataType 

MaxValue 

MinValue 

Create 

Owner