为dataset的多个表定义表间关系，并输出主从表

为dataset的多个表定义表间关系，并输出主从表：

 

// 创建dataset

 

 string constr = "server=(local);uid=sa;pwd=123456; database=信息中心科技资料管理数据库";
            SqlConnection con = new SqlConnection(constr);

            string  com1 = "select * from 资料信息表";
            string  com2 = "select * from 资料借阅表";

            SqlDataAdapter ada1 = new SqlDataAdapter(com1,con);

            SqlDataAdapter ada2 = new SqlDataAdapter(com2,con);

            DataSet ds = new DataSet();

            ada1.Fill(ds, "资料信息表");
            ada2.Fill(ds, "资料借阅表");

 

//定义表间关系

 

 ds.Relations.Add("关系名", ds.Tables["主表"].Columns["主表主键"], ds.Tables["从表"].Columns["从表外键"]);

 

 

 

//由主表找出从有并输出

 

    foreach (DataRow perrow in ds.Tables["资料信息表"].Rows)
            {
                DataRow[] chilrow =perrow.GetChildRows("rel");              //"rel"关系名
                int roomCount = chilrow.Length;
                Console.WriteLine("档号 {0} 行数 {1} 借阅信息：{2}", perrow["档号"], roomCount,roomCount > 1 ? "--" : "");

                foreach (DataRow theRoom in chilrow)

                    Console.WriteLine("借阅人: {0}", theRoom["借阅人"]);

            }

 

//由从表找到主表并输出

 

 foreach (DataRow theChild in ds.Tables["资料借阅表"].Rows)
            {

                DataRow[] parents = theChild.GetParentRows("rel");

                foreach (DataRow thePar in parents)

                    Console.WriteLine("借阅人： {0} 被借阅的档号： {1}",

                                      theChild["借阅人"],

                                      thePar["档号"]);

            }