Tài liệu Reading XML Data Directly from SQL Server doc

[ Team LiB ]Recipe 8.5 Reading XML Data Directly from SQL Server Problem You need to read XML data directly from the SQL Server.. File: ReadXmlDirectForm.cs // Namespaces, variables,

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Recipe 8.5 Reading XML Data Directly from SQL Server

Problem

You need to read XML data directly from the SQL Server

Solution

Use the FOR XML clause in the stored procedure or SQL statement

The C# code is shown in Example 8-8

Example 8-8 File: ReadXmlDirectForm.cs

// Namespaces, variables, and constants

using System;

using System.Configuration;

using System.Xml;

using System.Data;

using System.Data.SqlClient;

//

// Select statement to read XML directly

String sqlText = "SELECT * FROM Orders FOR XML AUTO, XMLDATA";

// Create the connection

SqlConnection conn = new SqlConnection(

ConfigurationSettings.AppSettings["Sql_ConnectString"]);

conn.Open( );

// Create the command

SqlCommand cmd = new SqlCommand(sqlText, conn);

// Read the XML data into a XML reader

XmlReader xr = cmd.ExecuteXmlReader( );

// Read the data from the XML reader into the DataSet

DataSet ds = new DataSet( );

ds.ReadXml(xr, XmlReadMode.Fragment);

xr.Close( );

conn.Close( );

xmlTextBox.Text = ds.GetXml( );

Discussion

SQL Server 2000 introduced support for retrieving data in XML format using the FOR XML clause The NET SQL Server data provider SqlCommand object has an

ExecuteXmlReader( ) that allows you to retrieve an XML stream directly from SQL Server, where it returns an XmlReader that contains the results of the SQL query The ExecuteXmlReader( ) method can only be used with SQL statements that return XML data, such as those with a FOR XML clause The ExecuteXmlReader( ) method can also

be used to return ntext data containing valid XML

For more information about the FOR XML clause, see Microsoft SQL Server Books Online

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