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;