Open Method (ADO Connection)

Opens a connection to a data source.


connection.Open ConnectionString, UserID, Password, Options  


Optional. A String value that contains connection information. See the ConnectionString property for details on valid settings.

Optional. A String value that contains a user name to use when establishing the connection.

Optional. A String value that contains a password to use when establishing the connection.

Optional. A ConnectOptionEnum value that determines whether this method should return after (synchronously) or before (asynchronously) the connection is established.


Using the Open method on a Connection object establishes the physical connection to a data source. After this method successfully completes, the connection is live and you can issue commands against it and process the results.

Use the optional ConnectionString argument to specify either a connection string containing a series of argument = value statements separated by semicolons, or a file or directory resource identified with a URL. The ConnectionString property automatically inherits the value used for the ConnectionString argument. Therefore, you can either set the ConnectionString property of the Connection object before opening it, or use the ConnectionString argument to set or override the current connection parameters during the Open method call.

If you pass user and password information both in the ConnectionString argument and in the optional UserID and Password arguments, the UserID and Password arguments will override the values specified in ConnectionString.

When you have concluded your operations over an open Connection, use the Close method to free any associated system resources. Closing an object does not remove it from memory; you can change its property settings and use the Open method to open it again later. To completely eliminate an object from memory, set the object variable to Nothing.


Remote Data Service Usage When used on a client-side Connection object, the Open method doesn't actually establish a connection to the server until a Recordset is opened on the Connection object.


URLs using the http scheme will automatically invoke the Microsoft OLE DB Provider for Internet Publishing. For more information, see Absolute and Relative URLs.

Applies To

Connection Object (ADO)

See Also

Open and Close Methods Example (VB)
Open and Close Methods Example (VBScript)
Open and Close Methods Example (VC++)
Open Method (ADO Record)
Open Method (ADO Recordset)
Open Method (ADO Stream)
OpenSchema Method