Subscriptions

The Subscriptions (meta_md_subscription) table defines the Messaging System's subscriptions.

• Creating a subscription links together a publisher and a subscriber to monitor for, and react to, some type of event. Its job is to say that when a given event happens (the result of a publisher's activities), the following subscriber will consume the message that is deposited in the message queue.

• Creating a subscription will cause messages to be written to the Messaging System's message queue by a publisher, and consumed from the message queue by a subscriber. It does so by identifying a publisher, and subscriber, and parameters for each in the form of subscription attributes.

• The messages will expire from the queue if they are not consumed within the number of days identified by the subscription's expiration days. When a subscription's expiration days value is zero, its messages will not expire; they will persist in the message queue until consumed.

• Messages are only written to the queue for active subscriptions, but once they are in the queue, they are subject to being consumed regardless of whether or not the subscription has been deactivated.

• Typically maintained by a user assigned the Meta Administrator role, but may be accessed by any user with sufficient permissions to access the view.

The following list defines every field available in the subscriptions (md_subscription) table in alphabetical order:

• Created By - displays the name of the user who created the record you are viewing or maintaining. May not be overridden.

• Created On - displays the date on which the record that you are creating or maintaining was created. May not be overridden. May also represent the creation date of the records you are attempting to retrieve.

• Expiration Days - a value of zero indicates that the subscription's messages will not expire.
  • A positive integer value will indicate the number of days the subscription's messages will persist in the message queue. A message that is not consumed within this period will be expired (deleted) without being consumed by the subscriber.

• Is Active - the following options are available: Yes and No.
  • A value of Yes indicates that messages should be published for this subscription.

  • A value of No indicates that messages should not be published for this subscription. However, any message that had already been published is subject to being consumed.

• Modification Counter - this field is not maintainable. The date and time a given record was last modified.

• Modified By - this field is not maintainable. The user or system process that last modified the record.

• Modified On - this field is not maintainable. The date on which the record was last modified.

• Publisher Name - the foreign key to the publisher entity.

• Subscriber Name - the foreign key to the subscriber entity.

• Subscription Name - the unique identifier.

For the functionality of each action (i.e. button) available on this view, refer to the About the Actions topic.