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Valeurs de colonne SQL XML

SQL Server prend en charge le xml type de données. Utilisez la classe SqlCommand pour récupérer les jeux de résultats qui incluent ce type. Vous pouvez récupérer des colonnes xml via le SqlDataReader, comme les autres colonnes. Pour utiliser leur contenu en tant que XML, utilisez le XmlReader.

Exemple :

L’application console suivante sélectionne deux lignes, chacune avec une colonne xml, dans la base de données AdventureWorks de Sales.Store. Pour chaque ligne, le code appelle GetSqlXml et utilise CreateReader() pour créer le XmlReader. Pour conserver la valeur comme SqlXml à la place, utilisez directement la valeur renvoyée par GetSqlXml. La GetValue méthode retourne la xml valeur de colonne sous forme de chaîne.

Remarque

L’exemple AdventureWorks de base de données n’est pas installé par défaut lorsque vous installez SQL Server. Vous pouvez l’installer en exécutant le programme d’installation de SQL Server.

// Example assumes the following directives:
//     using Microsoft.Data.SqlClient;
//     using System.Xml;
//     using System.Data.SqlTypes;

static void GetXmlData(string connectionString)
{
    using (SqlConnection connection = new(connectionString))
    {
        connection.Open();

        // The query includes two specific customers for simplicity's
        // sake. A more realistic approach would use a parameter
        // for the CustomerID criteria. The example selects two rows
        // in order to demonstrate reading first from one row to
        // another, then from one node to another within the xml column.
        const string commandText =
            "SELECT Demographics from Sales.Store WHERE " +
            "CustomerID = 3 OR CustomerID = 4";

        SqlCommand commandSales = new(commandText, connection);

        SqlDataReader salesReaderData = commandSales.ExecuteReader();

        //  Multiple rows are returned by the SELECT, so each row
        //  is read and an XmlReader (an xml data type) is set to the
        //  value of its first (and only) column.
        var countRow = 1;
        while (salesReaderData.Read())
        //  Must use GetSqlXml here to get a SqlXml type.
        //  GetValue returns a string instead of SqlXml.
        {
            SqlXml salesXML =
                salesReaderData.GetSqlXml(0);
            XmlReader salesReaderXml = salesXML.CreateReader();
            Console.WriteLine("-----Row " + countRow + "-----");

            //  Move to the root.
            salesReaderXml.MoveToContent();

            //  We know each node type is either Element or Text.
            //  All elements within the root are string values.
            //  For this simple example, no elements are empty.
            while (salesReaderXml.Read())
            {
                if (salesReaderXml.NodeType == XmlNodeType.Element)
                {
                    var elementLocalName =
                        salesReaderXml.LocalName;
                    salesReaderXml.Read();
                    Console.WriteLine(elementLocalName + ": " +
                        salesReaderXml.Value);
                }
            }
            countRow++;
        }
    }
}

' Example assumes the following directives:
'    Imports Microsoft.Data.SqlClient
'    Imports System.Xml
'    Imports System.Data.SqlTypes

Private Sub GetXmlData(ByVal connectionString As String)
    Using connection As SqlConnection = New SqlConnection(connectionString)
        connection.Open()

        'The query includes two specific customers for simplicity's
        'sake. A more realistic approach would use a parameter
        'for the CustomerID criteria. The example selects two rows
        'in order to demonstrate reading first from one row to
        'another, then from one node to another within the xml
        'column.
        Dim commandText As String = _
         "SELECT Demographics from Sales.Store WHERE " & _
         "CustomerID = 3 OR CustomerID = 4"

        Dim commandSales As New SqlCommand(commandText, connection)

        Dim salesReaderData As SqlDataReader = commandSales.ExecuteReader()

        ' Multiple rows are returned by the SELECT, so each row
        ' is read and an XmlReader (an xml data type) is set to the
        ' value of its first (and only) column.
        Dim countRow As Integer = 1
        While salesReaderData.Read()
            ' Must use GetSqlXml here to get a SqlXml type.
            ' GetValue returns a string instead of SqlXml.
            Dim salesXML As SqlXml = _
             salesReaderData.GetSqlXml(0)
            Dim salesReaderXml As XmlReader = salesXML.CreateReader()

            Console.WriteLine("-----Row " & countRow & "-----")

            ' Move to the root.
            salesReaderXml.MoveToContent()

            ' We know each node type is either Element or Text.
            ' All elements within the root are string values.
            ' For this simple example, no elements
            ' are empty.
            While salesReaderXml.Read()
                If salesReaderXml.NodeType = XmlNodeType.Element Then
                    Dim elementLocalName As String = _
                     salesReaderXml.LocalName
                    salesReaderXml.Read()
                    Console.WriteLine(elementLocalName & ": " & _
                     salesReaderXml.Value)
                End If
            End While
            countRow = countRow + 1
        End While
    End Using
End Sub

Voir aussi

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