Represents an open connection to a data source.
Assembly: System.Data (in System.Data.dll)
Gets or sets the string used to open a data source.(Overrides DbConnection.ConnectionString.)
Gets or sets the time to wait while trying to establish a connection before terminating the attempt and generating an error.
Gets the name of the current database or the database to be used after a connection is opened.(Overrides DbConnection.Database.)
Gets the server name or file name of the data source.(Overrides DbConnection.DataSource.)
Gets the name of the ODBC driver specified for the current connection.
Gets a string that contains the version of the server to which the client is connected.(Overrides DbConnection.ServerVersion.)
Gets the current state of the connection.(Overrides DbConnection.State.)
Starts a transaction at the data source.
Starts a transaction at the data source with the specified IsolationLevel value.
Changes the current database associated with an open DbConnection.ChangeDatabase(String).).(Overrides
Closes the connection to the data source. (Overrides DbConnection.Close().)
Creates and returns an OdbcCommand object associated with the .
Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.)
Enlists in the specified transaction as a distributed transaction.
Enlists in the specified transaction as a distributed transaction.(Overrides DbConnection.EnlistTransaction(Transaction).)
Determines whether the specified object is equal to the current object.(Inherited from Object.)
Serves as the default hash function. (Inherited from Object.)
Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)
Returns schema information for the data source of this DbConnection.GetSchema().).(Overrides
Returns schema information for the data source of this DbConnection.GetSchema(String).)using the specified name for the schema name.(Overrides
Returns schema information for the data source of this DbConnection.GetSchema(String, String()).)using the specified string for the schema name and the specified string array for the restriction values.(Overrides
Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)
This is the asynchronous version of Open. Providers should override with an appropriate implementation. The cancellation token can optionally be honored.
The default implementation invokes the synchronous Open call and returns a completed task. The default implementation will return a cancelled task if passed an already cancelled cancellationToken. Exceptions thrown by Open will be communicated via the returned Task Exception property.
Do not invoke other methods and properties of the DbConnection object until the returned Task is complete.(Inherited from DbConnection.)
Indicates that the ODBC Driver Manager environment handle can be released when the last underlying connection is released.
Begins a database transaction.(Inherited from DbConnection.)
For a description of this member, see ICloneable.Clone.
Anobject represents a unique connection to a data source created by using a connection string or ODBC data source name (DSN). With a client/server database system, it is equivalent to a network connection to the server. Depending on the functionality supported by the native ODBC driver, some methods or properties of an object may not be available.
The Close or Dispose before the object goes out of scope, or by placing the connection within a Using statement. Not doing this leaves the freeing of these native resources to garbage collection. It might not free them immediately. This, in turn, can eventually cause the underlying driver to run out of resources or reach a maximum limit. This has resulted in intermittent failures. For example, you might experience Maximum Connections -related errors while many connections are waiting to be deleted by the garbage collector. Explicitly closing the connections allows for a more efficient use of native resources, enhancing scalability and improving overall application performance.object uses native resources such as ODBC environment and connection handles. You should always explicitly close any open objects by calling
To deploy high-performance applications, you frequently must use connection pooling. However, when you use the .NET Framework Data Provider for ODBC, you do not have to enable connection pooling because the provider manages this automatically.
If one of the Execute methods of the OdbcCommand class causes a fatal OdbcException (for example, a SQL Server severity level of 20 or greater), the may close. However, the user can reopen the connection and continue.
An application that creates an instance of the OdbcPermission object. Users can verify that their code has sufficient permissions by using the OdbcPermissionAttribute object. Users and administrators can also use the Code Access Security Policy Tool (Caspol.exe) to modify security policy at the computer, user, and enterprise levels. For more information, see Code Access Security and ADO.NET.object can require all direct and indirect callers to have sufficient permission to the code by setting declarative or imperative security demands. creates security demands by using the
For more information about handling warning and informational messages from the data source, see Connection Events.
The following example creates an OdbcCommand and an . The is opened and set as the Connection property. The example then calls ExecuteNonQuery, and closes the connection. To accomplish this, the ExecuteNonQuery is passed a connection string and a query string that is an SQL INSERT statement.
Private Sub InsertRow(ByVal connectionString As String) Dim queryString As String = _ "INSERT INTO Customers (CustomerID, CompanyName) Values('NWIND', 'Northwind Traders')" Dim command As New OdbcCommand(queryString) Using connection As New OdbcConnection(connectionString) command.Connection = connection connection.Open() command.ExecuteNonQuery() ' The connection is automatically closed at ' the end of the Using block. End Using End Sub
Available since 1.1
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.