OdbcConnection Class

Definition

Namespace:

System.Data.Odbc

Assembly:

System.Data.Odbc.dll

Package:

System.Data.Odbc v11.0.0-preview.3.26207.106

Source:

OdbcConnection.cs

Represents an open connection to a data source.

public ref class OdbcConnection sealed : System::Data::Common::DbConnection, ICloneable

public sealed class OdbcConnection : System.Data.Common.DbConnection, ICloneable

type OdbcConnection = class
    inherit DbConnection
    interface ICloneable

Public NotInheritable Class OdbcConnection
Inherits DbConnection
Implements ICloneable

Inheritance

Object

MarshalByRefObject

Component

DbConnection

OdbcConnection

Implements

ICloneable

Examples

The following example creates an OdbcCommand and an OdbcConnection. The OdbcConnection 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.

static private void InsertRow(string connectionString)
{
    string queryString =
        "INSERT INTO Customers (CustomerID, CompanyName) Values('NWIND', 'Northwind Traders')";
    OdbcCommand command = new OdbcCommand(queryString);

    using (OdbcConnection connection = new OdbcConnection(connectionString))
    {
        command.Connection = connection;
        connection.Open();
        command.ExecuteNonQuery();

        // The connection is automatically closed at
        // the end of the Using block.
    }
}

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

Remarks

An OdbcConnection object 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 OdbcConnection object may not be available.

The OdbcConnection object uses native resources such as ODBC environment and connection handles. You should always explicitly close any open OdbcConnection objects by calling Close or Dispose before the OdbcConnection 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.

Note

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 OdbcConnection may close. However, the user can reopen the connection and continue.

An application that creates an instance of the OdbcConnection object can require all direct and indirect callers to have sufficient permission to the code by setting declarative or imperative security demands. OdbcConnection creates security demands by using 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.

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

Constructors

Name	Description
OdbcConnection()	Initializes a new instance of the OdbcConnection class.
OdbcConnection(String)	Initializes a new instance of the OdbcConnection class with the specified connection string.

Properties

Name	Description
ConnectionString	Gets or sets the string used to open a data source.
ConnectionTimeout	Gets or sets 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.
Driver	Gets the name of the ODBC driver specified for the current connection.
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

Name	Description
BeginTransaction()	Starts a transaction at the data source.
BeginTransaction(IsolationLevel)	Starts a transaction at the data source with the specified IsolationLevel value.
ChangeDatabase(String)	Changes the current database associated with an open OdbcConnection.
Close()	Closes the connection to the data source.
CreateCommand()	Creates and returns an OdbcCommand object associated with the OdbcConnection.
GetSchema()	Returns schema information for the data source of this OdbcConnection.
GetSchema(String, String[])	Returns schema information for the data source of this OdbcConnection 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 OdbcConnection using the specified name for the schema name.
Open()	Opens a connection to a data source with the property settings specified by the ConnectionString.
ReleaseObjectPool()	Indicates that the ODBC Driver Manager environment handle can be released when the last underlying connection is released.

Events

Name	Description
InfoMessage	Occurs when the ODBC driver sends a warning or an informational message.

Explicit Interface Implementations

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

See also

• Connecting to Data Sources