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Navigating Between Parent and Child Records Using a DataRelation

[ Team LiB ] Recipe 3.4 Navigating Between Parent and Child Records Using a DataRelation Problem You want to navigate between the parent and child records in a hierarchical DataSet. Solution Use a DataRelation to find the child rows | Team LiB Recipe 3.4 Navigating Between Parent and Child Records Using a DataRelation Problem You want to navigate between the parent and child records in a hierarchical DataSet. Solution Use a DataRelation to find the child rows for a parent row in a related table or to find the parent row for a child row in a related table. The sample code starts by creating a DataSet containing the Orders and Order Details tables from the Northwind sample database and a relation between them. The code then iterates over the Orders and uses the relation to return all Order Detail rows for each order. Finally the sample code retrieves the CustomerlD field from the parent row and displays it for each child. The C code is shown in Example 3-4. Example 3-4. File NavigateDataRelationForm.cs Namespaces variables and constants using System using System.Configuration using System.Text using System.Data using System.Data.SqlClient Table name constants private const String ORDERS_TABLE Orders private const String ORDERDETAILS_TABLE OrderDetails Relation name constants private const String ORDERS_ORDERDETAILS_RELATION Orders_OrderDetails_Relation Field name constants private const String ORDERID_FIELD OrderlD private const String PRODUCTID_FIELD ProductID private const String QUANTITY_FIELD Quantity private const String CUSTOMERID_FIELD CustomerID . . . DataSet ds new DataSet SqlDataAdapter da Fill the Order table and add it to the DataSet. da new SqlDataAdapter SELECT FROM Orders ConfigurationSettings.AppSettings Sql_ConnectString DataTable orderTable new DataTable ORDERS_TABLE da.Fill orderTable ds.Tables. Add orderT able Fill the OrderDetails table and add it to the DataSet. da new SqlDataAdapter SELECT FROM Order Details ConfigurationSettings.AppSettings Sql_ConnectString DataTable orderDetailTable new DataTable ORDERDETAILS_TABLE da.Fill orderDetailTable ds.Tables.Add orderDetailTable Create a relation between the tables. ds.Relations.Add ORDERS_ORDERDETAILS_RELATION ds.Tables .