IDbConnection Interface

Definição

public interface class IDbConnection : IDisposable

public interface IDbConnection : IDisposable

type IDbConnection = interface
    interface IDisposable

Public Interface IDbConnection
Implements IDisposable

Derivado

System.Data.Common.DbConnection

System.Data.OleDb.OleDbConnection

System.Data.SqlClient.SqlConnection

Implementações

IDisposable

Exemplos

O exemplo a seguir cria instâncias das classes derivadas, SqlCommand e SqlConnection.The following example creates instances of the derived classes, SqlCommand and SqlConnection. O SqlConnection é aberto e definido como o Connection para o SqlCommand.The SqlConnection is opened and set as the Connection for the SqlCommand. Em seguida, o exemplo chama ExecuteNonQuerye fecha a conexão.The example then calls ExecuteNonQuery, and closes the connection. Para fazer isso, a ExecuteNonQuery é passada uma cadeia de conexão e uma cadeia de caracteres de consulta que é uma instrução INSERT do Transact-SQL.To accomplish this, the ExecuteNonQuery is passed a connection string and a query string that is a Transact-SQL INSERT statement.

using System;
using System.Data;

namespace IDbConnectionSample {
   class Program {
      static void Main(string[] args) {
         IDbConnection connection;

         // First use a SqlClient connection
         connection = new System.Data.SqlClient.SqlConnection(@"Server=(localdb)\V11.0");
         Console.WriteLine("SqlClient\r\n{0}", GetServerVersion(connection));
         connection = new System.Data.SqlClient.SqlConnection(@"Server=(local);Integrated Security=true");
         Console.WriteLine("SqlClient\r\n{0}", GetServerVersion(connection));

         // Call the same method using ODBC
         // NOTE: LocalDB requires the SQL Server 2012 Native Client ODBC driver
         connection = new System.Data.Odbc.OdbcConnection(@"Driver={SQL Server Native Client 11.0};Server=(localdb)\v11.0");
         Console.WriteLine("ODBC\r\n{0}", GetServerVersion(connection));
         connection = new System.Data.Odbc.OdbcConnection(@"Driver={SQL Server Native Client 11.0};Server=(local);Trusted_Connection=yes");
         Console.WriteLine("ODBC\r\n{0}", GetServerVersion(connection));

         // Call the same method using OLE DB
         connection = new System.Data.OleDb.OleDbConnection(@"Provider=SQLNCLI11;Server=(localdb)\v11.0;Trusted_Connection=yes;");
         Console.WriteLine("OLE DB\r\n{0}", GetServerVersion(connection));
         connection = new System.Data.OleDb.OleDbConnection(@"Provider=SQLNCLI11;Server=(local);Trusted_Connection=yes;");
         Console.WriteLine("OLE DB\r\n{0}", GetServerVersion(connection));
         }

      public static string GetServerVersion(IDbConnection connection) {
         // Ensure that the connection is opened (otherwise executing the command will fail)
         ConnectionState originalState = connection.State;
         if (originalState != ConnectionState.Open)
            connection.Open();
         try {
            // Create a command to get the server version
            // NOTE: The query's syntax is SQL Server specific
            IDbCommand command = connection.CreateCommand();
            command.CommandText = "SELECT @@version";
            return (string)command.ExecuteScalar();
         }
         finally {
            // Close the connection if that's how we got it
            if (originalState == ConnectionState.Closed)
               connection.Close();
         }
      }
   }
}

Imports System.Data

Class Program

    Public Shared Sub Main(args As String())

        Dim connection As IDbConnection



        ' First use a SqlClient connection

        connection = New System.Data.SqlClient.SqlConnection("Server=(localdb)\V11.0")

        Console.WriteLine("SqlClient" & vbCr & vbLf & "{0}", GetServerVersion(connection))

        connection = New System.Data.SqlClient.SqlConnection("Server=(local);Integrated Security=true")

        Console.WriteLine("SqlClient" & vbCr & vbLf & "{0}", GetServerVersion(connection))



        ' Call the same method using ODBC

        ' NOTE: LocalDB requires the SQL Server 2012 Native Client ODBC driver

        connection = New System.Data.Odbc.OdbcConnection("Driver={SQL Server Native Client 11.0};Server=(localdb)\v11.0")

        Console.WriteLine("ODBC" & vbCr & vbLf & "{0}", GetServerVersion(connection))

        connection = New System.Data.Odbc.OdbcConnection("Driver={SQL Server Native Client 11.0};Server=(local);Trusted_Connection=yes")

        Console.WriteLine("ODBC" & vbCr & vbLf & "{0}", GetServerVersion(connection))


        ' Call the same method using OLE DB

        connection = New System.Data.OleDb.OleDbConnection("Provider=SQLNCLI11;Server=(localdb)\v11.0;Trusted_Connection=yes;")

        Console.WriteLine("OLE DB" & vbCr & vbLf & "{0}", GetServerVersion(connection))

        connection = New System.Data.OleDb.OleDbConnection("Provider=SQLNCLI11;Server=(local);Trusted_Connection=yes;")

        Console.WriteLine("OLE DB" & vbCr & vbLf & "{0}", GetServerVersion(connection))

    End Sub



    Public Shared Function GetServerVersion(connection As IDbConnection) As String

        ' Ensure that the connection is opened (otherwise executing the command will fail)

        Dim originalState As ConnectionState = connection.State

        If originalState <> ConnectionState.Open Then

            connection.Open()

        End If

        Try

            ' Create a command to get the server version

            ' NOTE: The query's syntax is SQL Server specific

            Dim command As IDbCommand = connection.CreateCommand()

            command.CommandText = "SELECT @@version"

            Return DirectCast(command.ExecuteScalar(), String)

        Finally

            ' Close the connection if that's how we got it

            If originalState = ConnectionState.Closed Then

                connection.Close()

            End If

        End Try

    End Function

End Class

Comentários

A interface IDbConnection permite que uma classe de herança implemente uma classe Connection, que representa uma sessão exclusiva com uma fonte de dados (por exemplo, uma conexão de rede com um servidor).The IDbConnection interface enables an inheriting class to implement a Connection class, which represents a unique session with a data source (for example, a network connection to a server). Para obter mais informações sobre classes de conexão, consulte conectando-se a uma fonte de dados.For more information about Connection classes, see Connecting to a Data Source.

Um aplicativo não cria uma instância da interface de IDbConnection diretamente, mas cria uma instância de uma classe que herda IDbConnection.An application does not create an instance of the IDbConnection interface directly, but creates an instance of a class that inherits IDbConnection.

Classes que herdam IDbConnection devem implementar todos os membros herdados e geralmente definem membros adicionais para adicionar funcionalidade específica do provedor.Classes that inherit IDbConnection must implement all inherited members, and typically define additional members to add provider-specific functionality. Por exemplo, a interface IDbConnection define a propriedade ConnectionTimeout.For example, the IDbConnection interface defines the ConnectionTimeout property. Por sua vez, a classe SqlConnection herda essa propriedade e também define a propriedade PacketSize.In turn, the SqlConnection class inherits this property, and also defines the PacketSize property.

Notas aos Implementadores

Para promover a consistência entre .NET Framework provedores de dados, nomeie a classe herdeira no formulário PrvClassname em que Prv é o prefixo uniforme fornecido a todas as classes em um namespace específico do provedor de dados .NET Framework.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. Por exemplo, Sql é o prefixo da classe SqlConnection no namespace System.Data.SqlClient.For example, Sql is the prefix of the SqlConnection class in the System.Data.SqlClient namespace.

Ao herdar da interface IDbConnection, você deve implementar os seguintes construtores:When you inherit from the IDbConnection interface, you should implement the following constructors:

Propriedades

Métodos

Aplica-se a