в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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2010-05-26T12:19:09Z

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==DataRelation Example==

<source lang="csharp">using System;
using System.Data;
using System.Data.SqlClient;
using System.Collections.Generic;
using System.Text;
class Program
{
static void Main(string[] args)
{
SqlConnection thisConnection = new SqlConnection(
@"Data Source=.\SQLEXPRESS;" +
@"AttachDbFilename="NORTHWND.MDF";" +
@"Integrated Security=True;Connect Timeout=30;User Instance=true");
SqlDataAdapter thisAdapter = new SqlDataAdapter("SELECT CustomerID, CompanyName FROM Customers", thisConnection);
SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);
DataSet thisDataSet = new DataSet();
SqlDataAdapter custAdapter = new SqlDataAdapter("SELECT * FROM Customers", thisConnection);
SqlDataAdapter orderAdapter = new SqlDataAdapter("SELECT * FROM Orders", thisConnection);
custAdapter.Fill(thisDataSet, "Customers");
orderAdapter.Fill(thisDataSet, "Orders");
DataRelation custOrderRel = thisDataSet.Relations.Add("CustOrders",
thisDataSet.Tables["Customers"].Columns["CustomerID"],
thisDataSet.Tables["Orders"].Columns["CustomerID"]);
foreach (DataRow custRow in thisDataSet.Tables["Customers"].Rows)
{
Console.WriteLine("Customer ID: " + custRow["CustomerID"] +
" Name: " + custRow["CompanyName"]);
foreach (DataRow orderRow in custRow.GetChildRows(custOrderRel))
{
Console.WriteLine(" Order ID: " + orderRow["OrderID"]);
}
}
custOrderRel.Nested = true;
thisDataSet.WriteXml("nwinddata.xml");
thisConnection.Close();
}
}</source>

==Define DataRelation==

<source lang="csharp">using System;
using System.Data;
using System.Data.SqlClient;
public class XmlRelations
{
private static string connectionString = "Data Source=localhost;Initial Catalog=Northwind;Integrated Security=SSPI";
private static string categorySQL = "SELECT CategoryID, CategoryName,Description FROM Categories";
private static string productSQL = "SELECT ProductID, ProductName, CategoryID FROM Products";
public static void Main()
{
SqlConnection con = new SqlConnection(connectionString);
SqlCommand com = new SqlCommand(categorySQL, con);
SqlDataAdapter adapter = new SqlDataAdapter(com);
DataSet ds = new DataSet("Nortwind");
con.Open();
adapter.FillSchema(ds, SchemaType.Mapped, "Categories");
adapter.Fill(ds, "Categories");
adapter.SelectCommand.rumandText = productSQL;
adapter.FillSchema(ds, SchemaType.Mapped, "Products");
adapter.Fill(ds, "Products");
con.Close();
DataColumn parentCol = ds.Tables["Categories"].Columns["CategoryID"];
DataColumn childCol = ds.Tables["Products"].Columns["CategoryID"];
DataRelation relation = new DataRelation("Cat_Prod", parentCol, childCol);
ds.Relations.Add(relation);
relation.Nested = true;
ds.WriteXml("mydata.xml");
ds.WriteXml(Console.Out);
}
}</source>

==Navigate a many-to-many relationship.==

<source lang="csharp">using System;
using System.Data;
using System.Data.SqlClient;
public class AddCustomer
{
public static void Main()
{
string connectionString = "Data Source=localhost;Initial Catalog=pubs;Integrated Security=SSPI";
string SQL = "SELECT au_lname, au_fname, au_id FROM Authors";
SqlConnection con = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand(SQL, con);
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
con.Open();
adapter.Fill(ds, "Authors");
cmd.rumandText = "SELECT au_id, title_id FROM TitleAuthor";
adapter.Fill(ds, "TitleAuthor");
cmd.rumandText = "SELECT title_id, title FROM Titles";
adapter.Fill(ds, "Titles");
con.Close();
DataRelation titles_titleAuthor = new DataRelation("", ds.Tables["Titles"].Columns["title_id"], ds.Tables["TitleAuthor"].Columns["title_id"]);
DataRelation authors_titleAuthor = new DataRelation("", ds.Tables["Authors"].Columns["au_id"], ds.Tables["TitleAuthor"].Columns["au_id"]);
ds.Relations.Add(titles_titleAuthor);
ds.Relations.Add(authors_titleAuthor);
foreach (DataRow rowAuthor in ds.Tables["Authors"].Rows)
{
Console.WriteLine(rowAuthor["au_fname"]);
Console.WriteLine(rowAuthor["au_lname"]);
foreach (DataRow rowTitleAuthor in rowAuthor.GetChildRows(authors_titleAuthor))
{
foreach (DataRow rowTitle in rowTitleAuthor.GetParentRows(titles_titleAuthor))
{
Console.WriteLine(rowTitle["title"]);
}
}
}
}
}</source>

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в 15:31, 26 мая 2010

Admin: 1 версия