我在加载事件中写了这段代码:
private DataSet1 ds1 = new DataSet1();
private SqlDataAdapter da1 = new SqlDataAdapter();
ds1.Clear();
da1 = new SqlDataAdapter("select * from Département, division,Sérvice where Département.Num_Département = Division.Num_Département_Département and Sérvice.Num_Division_Division = Division.Num_Division", sql.cn);
da1.Fill(ds1, "Sérvice");
da1.Fill(ds1, "Division");
da1.Fill(ds1, "Département");
但是当我运行表单时它会给我这个错误:
无法启用约束。一行或多行包含值 违反非空,唯一或外键约束。
我该怎么办?