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SqlCommand Class

Represents a Transact-SQL statement or stored procedure to execute against a SQL Server database. This class cannot be inherited.

Namespace: System.Data.SqlClient
Assembly: System.Data (in system.data.dll)

'Declaration
Public NotInheritable Class SqlCommand
	Inherits DbCommand
	Implements ICloneable
'Usage
Dim instance As SqlCommand

public final class SqlCommand extends DbCommand implements ICloneable
public final class SqlCommand extends DbCommand implements ICloneable
Not applicable.

When an instance of SqlCommand is created, the read/write properties are set to their initial values. For a list of these values, see the SqlCommand constructor.

SqlCommand features the following methods for executing commands at a SQL Server database:

Item

Description

BeginExecuteNonQuery

Initiates the asynchronous execution of the Transact-SQL statement or stored procedure that is described by this SqlCommand, generally executing commands such as INSERT, DELETE, UPDATE, and SET statements. Each call to BeginExecuteNonQuery must be paired with a call to EndExecuteNonQuery which finishes the operation, typically on a separate thread.

BeginExecuteReader

Initiates the asynchronous execution of the Transact-SQL statement or stored procedure that is described by this SqlCommand and retrieves one or more results sets from the server. Each call to BeginExecuteReader must be paired with a call to EndExecuteReader which finishes the operation, typically on a separate thread.

BeginExecuteXmlReader

Initiates the asynchronous execution of the Transact-SQL statement or stored procedure that is described by this SqlCommand. Each call to BeginExecuteXmlReader must be paired with a call to EndExecuteXmlReader, which finishes the operation, typically on a separate thread, and returns an XmlReader object.

ExecuteReader

Executes commands that return rows. For increased performance, ExecuteReader invokes commands using the Transact-SQL sp_executesql system stored procedure. Therefore, ExecuteReader might not have the effect that you want if used to execute commands such as Transact-SQL SET statements.

ExecuteNonQuery

Executes commands such as Transact-SQL INSERT, DELETE, UPDATE, and SET statements.

ExecuteScalar

Retrieves a single value (for example, an aggregate value) from a database.

ExecuteXmlReader

Sends the CommandText to the Connection and builds an XmlReader object.

You can reset the CommandText property and reuse the SqlCommand object. However, you must close the SqlDataReader before you can execute a new or previous command.

If a SqlException is generated by the method executing a SqlCommand, the SqlConnection remains open when the severity level is 19 or less. When the severity level is 20 or greater, the server ordinarily closes the SqlConnection. However, the user can reopen the connection and continue.

TopicLocation
Walkthrough: Displaying Hierarchical Data in a TreeView ControlBuilding ASP .NET Web Applications in Visual Studio

The following example creates a SqlConnection, a SqlCommand, and a SqlDataReader. The example reads through the data, writing it to the console. Finally, the example closes the SqlDataReader and then the SqlConnection.

Public Sub ReadOrderData(ByVal connectionString As String)
    Dim queryString As String = _
        "SELECT OrderID, CustomerID FROM dbo.Orders;"
    Using connection As New SqlConnection(connectionString)
        Dim command As New SqlCommand(queryString, connection)
        connection.Open()
        Dim reader As SqlDataReader = command.ExecuteReader()
        Try
            While reader.Read()
                Console.WriteLine(String.Format("{0}, {1}", _
                    reader(0), reader(1)))
            End While
        Finally
            ' Always call Close when done reading.
            reader.Close()
        End Try
    End Using
End Sub

System.Object
   System.MarshalByRefObject
     System.ComponentModel.Component
       System.Data.Common.DbCommand
        System.Data.SqlClient.SqlCommand

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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