Connection definitions provide MQe with information on how to locate and communicate with remote queue managers. The name of a connection definition is that of the remote queue manager to which it describes a route, thus there may only be one direct connection definition for a remote queue manager. As connection definitions define the MQe network they are held in permanent storage in the registry and therefore persist across instances of the queue manager.
The route created using a connection definition uses an internal object called a channel as the transport mechanism to send data between two queue managers. Channels may not be accessed directly by a user but configuration decisions made for a queue manager affects the behavior of a channel.
At the lowest level of the communications layers is the communications adapter. The reason they are mentioned here is that it is imperative the connection definition defines the same communications adapter class as the adapter class being used by the listener on the listening queue manager. If the communications adapters are not exactly the same a successful connection will not be made.
For the connection definition to create a successful connection to a remote queue manager it is necessary for the correct communications adapter, the correct network address of the listening queue manager and the correct listening location to be specified. If any of this information is incorrect it is not possible to make a connection to the remote queue manager.
As will be seen from the examples there is much repetitive code involved in creating then checking the reply for an administration message. It is therefore probably desirable to put this code into a common class that may be used by all classes creating and checking the replies of administration messages.
The full code for updating a connection definition and for deleting a connection definition may be found in the examples supplied with the MQe product.