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Connection Object

A Connection object represents an open connection to a data source.

Collections

Errors, Properties

Methods

BeginTrans, Close, CommitTrans, Execute, Open, OpenSchema, RollbackTrans

Properties

Attributes, CommandTimeout, ConnectionString, ConnectionTimeout, CursorLocation, DefaultDatabase, IsolationLevel, Mode, Provider, State, Version

Remarks

A Connection object represents a unique session with a data source. In the case of a client/server database system, it may be equivalent to an actual network connection to the server. Depending on the functionality supported by the provider, some collections, methods, or properties of a Connection object may not be available.

Using the collections, methods, and properties of a Connection object, you can do the following:

• Configure the connection before opening it with the ConnectionString, ConnectionTimeout, and Mode properties.
  
  
• Set the CursorLocation property to invoke the Client Cursor Provider, which supports batch updates.
  
  
• Set the default database for the connection with the DefaultDatabase property.
  
  
• Set the level of isolation for the transactions opened on the connection with the IsolationLevel property.
  
  
• Specify an OLE DB provider with the Provider property.
  
  
• Establish, and later break, the physical connection to the data source with the Open and Close methods.
  
  
• Execute a command on the connection with the Execute method and configure the execution with the CommandTimeout property.
  
  
• Manage transactions on the open connection, including nested transactions if the provider supports them, with the BeginTrans, CommitTrans, and RollbackTrans methods and the Attributes property.
  
  
• Examine errors returned from the data source with the Errors collection.
  
  
• Read the version from the ADO implementation in use with the Version property.
  
  
• Obtain schema information about your database with the OpenSchema method.

Note To execute a query without using a Command object, pass a query string to the Execute method of a Connection object. However, a Command object is required when you want to persist the command text and re-execute it, or use query parameters.

You can create Connection objects independently of any other previously defined object.

See Also

Using OLE DB Providers with ADO

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