OleDbConnection Class

Definition

Namespace:

System.Data.OleDb

Assembly:

System.Data.OleDb.dll

Package:

System.Data.OleDb v9.0.0

Source:

OleDbConnection.cs

Represents an open connection to a data source.

public ref class OleDbConnection sealed : System::Data::Common::DbConnection, ICloneable, IDisposable

public sealed class OleDbConnection : System.Data.Common.DbConnection, ICloneable, IDisposable

type OleDbConnection = class
    inherit DbConnection
    interface IDbConnection
    interface IDisposable
    interface ICloneable

Public NotInheritable Class OleDbConnection
Inherits DbConnection
Implements ICloneable, IDisposable

Inheritance

Object

DbConnection

OleDbConnection

Implements

IDbConnection ICloneable IDisposable

Examples

The following example creates an OleDbCommand and an OleDbConnection. The OleDbConnection is opened and set as the Connection for the OleDbCommand. The example then calls ExecuteNonQuery and closes the connection. To accomplish this, ExecuteNonQuery is passed a connection string and a query string that is an SQL INSERT statement.

public void InsertRow(string connectionString, string insertSQL)
{
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        // The insertSQL string contains a SQL statement that
        // inserts a new row in the source table.
        OleDbCommand command = new OleDbCommand(insertSQL);

        // Set the Connection to the new OleDbConnection.
        command.Connection = connection;

        // Open the connection and execute the insert command.
        try
        {
            connection.Open();
            command.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
        // The connection is automatically closed when the
        // code exits the using block.
    }
}

Public Sub InsertRow(ByVal connectionString As String, _
    ByVal insertSQL As String)

    Using connection As New OleDbConnection(connectionString)
        ' The insertSQL string contains a SQL statement that
        ' inserts a new row in the source table.
        Dim command As New OleDbCommand(insertSQL)

        ' Set the Connection to the new OleDbConnection.
        command.Connection = connection

        ' Open the connection and execute the insert command.
        Try
            connection.Open()
            command.ExecuteNonQuery()
        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try
        ' The connection is automatically closed when the
        ' code exits the Using block.
    End Using
End Sub

Remarks

An OleDbConnection object represents a unique connection to a data source. With a client/server database system, it is equivalent to a network connection to the server. Depending on the functionality supported by the native OLE DB provider, some methods or properties of an OleDbConnection object may not be available.

When you create an instance of OleDbConnection, all properties are set to their initial values. For a list of these values, see the OleDbConnection constructor.

You can open more than one DataReader on a single OleDbConnection. If the OLE DB provider you use does not support more than one DataReader on a single connection, the provider implicitly opens an additional connection for each.

If the OleDbConnection goes out of scope, it is not closed. Therefore, you must explicitly close the connection by calling Close or Dispose, or by using the OleDbConnection object within a Using statement.

Note

To deploy high-performance applications, you must use connection pooling. When you use the .NET Framework Data Provider for OLE DB, you do not have to enable connection pooling because the provider manages this automatically. For more information about how to use connection pooling with the .NET Framework Data Provider for OLE DB, see OLE DB, ODBC, and Oracle Connection Pooling.

If a fatal OleDbException (for example, a SQL Server severity level of 20 or greater) is generated by the method executing an OleDbCommand, the OleDbConnection might be closed. However, the user can reopen the connection and continue.

An application that creates an instance of the OleDbConnection object can require all direct and indirect callers to have sufficient permission to the code by setting declarative or imperative security demands. OleDbConnection makes security demands using the OleDbPermission object. Users can verify that their code has sufficient permissions by using the OleDbPermissionAttribute object. Users and administrators can also use the Caspol.exe (Code Access Security Policy Tool) to modify security policy at the computer, user, and enterprise levels. For more information, see Code Access Security and ADO.NET.

For more information about handling warning and informational messages from the data server, see Connection Events.

Note

The OleDbConnection object does not support setting or retrieving dynamic properties specific to an OLE DB provider. Only properties that can be passed in the connection string for the OLE DB provider are supported.

Constructors

OleDbConnection()	Initializes a new instance of the OleDbConnection class.
OleDbConnection(String)	Initializes a new instance of the OleDbConnection class with the specified connection string.

Properties

CanCreateBatch	Gets a value that indicates whether this DbConnection instance supports the DbBatch class. (Inherited from DbConnection)
ConnectionString	Gets or sets the string used to open a database.
ConnectionTimeout	Gets the time to wait (in seconds) while trying to establish a connection before terminating the attempt and generating an error.
Database	Gets the name of the current database or the database to be used after a connection is opened.
DataSource	Gets the server name or file name of the data source.
DbProviderFactory	Gets the DbProviderFactory for this DbConnection. (Inherited from DbConnection)
Provider	Gets the name of the OLE DB provider specified in the "Provider= " clause of the connection string.
ServerVersion	Gets a string that contains the version of the server to which the client is connected.
State	Gets the current state of the connection.

Methods

BeginDbTransaction(IsolationLevel)	When overridden in a derived class, starts a database transaction. (Inherited from DbConnection)
BeginDbTransactionAsync(IsolationLevel, CancellationToken)	Asynchronously starts a database transaction. (Inherited from DbConnection)
BeginTransaction()	Starts a database transaction with the current IsolationLevel value.
BeginTransaction(IsolationLevel)	Starts a database transaction with the specified isolation level.
BeginTransactionAsync(CancellationToken)	Asynchronously begins a database transaction. (Inherited from DbConnection)
BeginTransactionAsync(IsolationLevel, CancellationToken)	Asynchronously begins a database transaction. (Inherited from DbConnection)
ChangeDatabase(String)	Changes the current database for an open OleDbConnection.
ChangeDatabaseAsync(String, CancellationToken)	Asynchronously changes the current database for an open connection. (Inherited from DbConnection)
Close()	Closes the connection to the data source.
CloseAsync()	Asynchronously closes the connection to the database. (Inherited from DbConnection)
CreateBatch()	Returns a new instance of the provider's class that implements the DbBatch class. (Inherited from DbConnection)
CreateCommand()	Creates and returns an OleDbCommand object associated with the OleDbConnection.
CreateDbBatch()	When overridden in a derived class, returns a new instance of the provider's class that implements the DbBatch class. (Inherited from DbConnection)
CreateDbCommand()	When overridden in a derived class, creates and returns a DbCommand object associated with the current connection. (Inherited from DbConnection)
Dispose()	Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources. (Inherited from DbConnection)
Dispose(Boolean)	Releases the unmanaged resources used by the DbConnection and optionally releases the managed resources. (Inherited from DbConnection)
DisposeAsync()	Asynchronously disposes the connection object. (Inherited from DbConnection)
EnlistTransaction(Transaction)	Enlists in the specified transaction as a distributed transaction.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetOleDbSchemaTable(Guid, Object[])	Returns schema information from a data source as indicated by a GUID, and after it applies the specified restrictions.
GetSchema()	Returns schema information for the data source of this OleDbConnection.
GetSchema(String, String[])	Returns schema information for the data source of this OleDbConnection using the specified string for the schema name and the specified string array for the restriction values.
GetSchema(String)	Returns schema information for the data source of this OleDbConnection using the specified string for the schema name.
GetSchemaAsync(CancellationToken)	This is an asynchronous version of GetSchema(). Providers should override with an appropriate implementation. The cancellationToken can optionally be honored. The default implementation invokes the synchronous GetSchema() call and returns a completed task. The default implementation will return a cancelled task if passed an already cancelled cancellationToken. Exceptions thrown by GetSchema() will be communicated via the returned Task Exception property. (Inherited from DbConnection)
GetSchemaAsync(String, CancellationToken)	This is the asynchronous version of GetSchema(String). Providers should override with an appropriate implementation. The cancellationToken can optionally be honored. The default implementation invokes the synchronous GetSchema(String) call and returns a completed task. The default implementation will return a cancelled task if passed an already cancelled cancellationToken. Exceptions thrown by GetSchema(String) will be communicated via the returned Task Exception property. (Inherited from DbConnection)
GetSchemaAsync(String, String[], CancellationToken)	This is the asynchronous version of GetSchema(String, String[]). Providers should override with an appropriate implementation. The cancellationToken can optionally be honored. The default implementation invokes the synchronous GetSchema(String, String[]) call and returns a completed task. The default implementation will return a cancelled task if passed an already cancelled cancellationToken. Exceptions thrown by GetSchema(String, String[]) will be communicated via the returned Task Exception property. (Inherited from DbConnection)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnStateChange(StateChangeEventArgs)	Raises the StateChange event. (Inherited from DbConnection)
Open()	Opens a database connection with the property settings specified by the ConnectionString.
OpenAsync()	An asynchronous version of Open(), which opens a database connection with the settings specified by the ConnectionString. This method invokes the virtual method OpenAsync(CancellationToken) with CancellationToken.None. (Inherited from DbConnection)
OpenAsync(CancellationToken)	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)
ReleaseObjectPool()	Indicates that the OleDbConnection object pool can be released when the last underlying connection is released.
ResetState()	Updates the State property of the OleDbConnection object.
ToString()	Returns a string that represents the current object. (Inherited from Object)

Events

InfoMessage	Occurs when the provider sends a warning or an informational message.
StateChange	Occurs when the state of the connection changes. (Inherited from DbConnection)

Explicit Interface Implementations

ICloneable.Clone()

For a description of this member, see Clone().

See also

• Connecting to Data Sources