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IDbCommand Interface

Represents an SQL statement that is executed while connected to a data source, and is implemented by .NET Framework data providers that access relational databases.

Namespace:  System.Data
Assembly:  System.Data (in System.Data.dll)
public interface IDbCommand : IDisposable

The IDbCommand type exposes the following members.

  NameDescription
Public propertySupported by the XNA FrameworkCommandTextGets or sets the text command to run against the data source.
Public propertySupported by the XNA FrameworkCommandTimeoutGets or sets the wait time before terminating the attempt to execute a command and generating an error.
Public propertySupported by the XNA FrameworkCommandTypeIndicates or specifies how the CommandText property is interpreted.
Public propertySupported by the XNA FrameworkConnectionGets or sets the IDbConnection used by this instance of the IDbCommand.
Public propertySupported by the XNA FrameworkParametersGets the IDataParameterCollection.
Public propertySupported by the XNA FrameworkTransactionGets or sets the transaction within which the Command object of a .NET Framework data provider executes.
Public propertySupported by the XNA FrameworkUpdatedRowSourceGets or sets how command results are applied to the DataRow when used by the Update method of a DbDataAdapter.
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  NameDescription
Public methodSupported by the XNA FrameworkCancelAttempts to cancels the execution of an IDbCommand.
Public methodSupported by the XNA FrameworkCreateParameterCreates a new instance of an IDbDataParameter object.
Public methodSupported by the XNA FrameworkDisposePerforms application-defined tasks associated with freeing, releasing, or resetting unmanaged resources. (Inherited from IDisposable.)
Public methodSupported by the XNA FrameworkExecuteNonQueryExecutes an SQL statement against the Connection object of a .NET Framework data provider, and returns the number of rows affected.
Public methodSupported by the XNA FrameworkExecuteReader()Executes the CommandText against the Connection and builds an IDataReader.
Public methodSupported by the XNA FrameworkExecuteReader(CommandBehavior)Executes the CommandText against the Connection, and builds an IDataReader using one of the CommandBehavior values.
Public methodSupported by the XNA FrameworkExecuteScalarExecutes the query, and returns the first column of the first row in the resultset returned by the query. Extra columns or rows are ignored.
Public methodSupported by the XNA FrameworkPrepareCreates a prepared (or compiled) version of the command on the data source.
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The IDbCommand interface enables an inheriting class to implement a Command class, which represents an SQL statement that is executed at a data source. For more information about Command classes, see Executing a Command (ADO.NET).

An application does not create an instance of the IDbCommand interface directly, but creates an instance of a class that inherits IDbCommand.

Classes that inherit IDbCommand must implement all inherited members, and typically define additional members to add provider-specific functionality. For example, the IDbCommand interface defines the ExecuteNonQuery method. In turn, the SqlCommand class inherits this method, and also defines the ExecuteXmlReader method.

Notes to Implementers

To promote consistency among .NET Framework data providers, name the inheriting class in the form PrvClassname where Prv is the uniform prefix given to all classes in a specific .NET Framework data provider namespace. For example, Sql is the prefix of the SqlCommand class in the System.Data.SqlClient namespace.

When you inherit from the IDbCommand interface, you should implement the following constructors:

Item

Description

PrvCommand()

Initializes a new instance of the PrvCommand class.

PrvCommand(string cmdText)

Initializes a new instance of the PrvCommand class with the text of the query.

PrvCommand(string cmdText, PrvConnection connection)

Initializes a new instance of the PrvCommand class with the text of the query and a PrvConnection.

PrvCommand(string cmdText, PrvConnection connection, PrvTransaction transaction)

Initializes a new instance of the PrvCommand class with the text of the query, a PrvConnection, and the PrvTransaction.

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


private static void ReadOrderData(string connectionString)
{
    string queryString = 
        "SELECT OrderID, CustomerID FROM dbo.Orders;";
    using (SqlConnection connection = new SqlConnection(
               connectionString))
    {
        SqlCommand command = new SqlCommand(
            queryString, connection);
        connection.Open();
        SqlDataReader reader = command.ExecuteReader();
        try
        {
            while (reader.Read())
            {
                Console.WriteLine(String.Format("{0}, {1}",
                    reader[0], reader[1]));
            }
        }
        finally
        {
            // Always call Close when done reading.
            reader.Close();
        }
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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