DataSet Relastion （1）

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因用一个小程序实现 dataset 各个表的关系。用到了relastion 先创建。

 private static void ConnectToData(string connectionString)        {            //Create a SqlConnection to the Northwind database.            using (SqlConnection connection =                       new SqlConnection(connectionString))            {                //Create a SqlDataAdapter for the Suppliers table.                SqlDataAdapter adapter = new SqlDataAdapter();                // A table mapping names the DataTable.                adapter.TableMappings.Add("Table", "Suppliers");                // Open the connection.                connection.Open();                Console.WriteLine("The SqlConnection is open.");                // Create a SqlCommand to retrieve Suppliers data.                SqlCommand command = new SqlCommand(                    "SELECT SupplierID, CompanyName FROM dbo.Suppliers;",                    connection);                command.CommandType = CommandType.Text;                // Set the SqlDataAdapter's SelectCommand.                adapter.SelectCommand = command;                // Fill the DataSet.                DataSet dataSet = new DataSet("Suppliers");                adapter.Fill(dataSet);                // Create a second Adapter and Command to get                // the Products table, a child table of Suppliers.                 SqlDataAdapter productsAdapter = new SqlDataAdapter();                productsAdapter.TableMappings.Add("Table", "Products");                SqlCommand productsCommand = new SqlCommand(                    "SELECT ProductID, SupplierID FROM dbo.Products;",                    connection);                productsAdapter.SelectCommand = productsCommand;                // Fill the DataSet.                productsAdapter.Fill(dataSet);                // Close the connection.                connection.Close();                Console.WriteLine("The SqlConnection is closed.");                // Create a DataRelation to link the two tables                // based on the SupplierID.                DataColumn parentColumn =                    dataSet.Tables["Suppliers"].Columns["SupplierID"];                DataColumn childColumn =                    dataSet.Tables["Products"].Columns["SupplierID"];                DataRelation relation =                    new System.Data.DataRelation("SuppliersProducts",                    parentColumn, childColumn);                dataSet.Relations.Add(relation);                Console.WriteLine(                    "The {0} DataRelation has been created.",                    relation.RelationName);            }        }

没有看晕吧

其实就一句话

getDS.Relations.Add("plan1", getDS.Tables[0].Columns["plan_Id"], getDS.Tables[1].Columns["plan_Id"]);

就可以了。如果报错提示什么关系已存在了。你就新建立一个dataset 然后再建立relastion