TClientDataSet[25]: 自动增长字段(ftAutoInc) 与字段默认值

自动增长字段:

---

//建立方法一:

begin

  with ClientDataSet1 do begin

    FieldDefs.Add('ID', ftAutoInc);

    FieldDefs.Add('Name', ftString, 11);

    CreateDataSet;

  end;

end;



//建立方法二:

begin

  with TAutoIncField.Create(Self) do begin

    FieldName := 'ID';

//    AutoGenerateValue := arAutoInc; { 不起作用 }

    DataSet := ClientDataSet1;

  end;

  with TStringField.Create(Self) do begin

    FieldName := 'Name';

    Size := 11;

    DataSet := ClientDataSet1;

  end;

  ClientDataSet1.CreateDataSet;

end;


 
   

字段默认值:

---

begin

  with TStringField.Create(Self) do begin

    FieldName := 'Name';

    Size := 11;

    DataSet := ClientDataSet1;

  end;

  with TIntegerField.Create(Self) do begin

    FieldName := 'Age';

    DefaultExpression := '18';

    DataSet := ClientDataSet1;

  end;

  ClientDataSet1.CreateDataSet;

end;