Locks

The Locks resource (meta_md_lock) is in the System Monitor module of iTopia. This view only works with tables that are set up as "transaction header" tables. The Locks view is used as part of the application-level locking procedure.

The Locks view is to perform the following operations:

• Query the records in the lock table.
• Delete the records in lock table.

This view serves as a means of determining the record that is being locked along with the user name of the user responsible for the lock, and the view associated with the lock.

• To examine only the records that your user id is currently locking, click the Profile menu option (found in the header section on any iTopia view or on any menu page) and select the My Locks view from the list of related resources.

The Locks table is automatically populated by the system whenever a user launches a transactional header table and then adds a new record through the Create action, or goes to the Details page of an existing record.

• Records are automatically deleted from this table when the user that is viewing a record in a transactional-type table clicks the Submit action, or when the user logs out of iTopia, in which case all locks held by the browser session are removed.

• If the browser fails or if the user closes the window without logging out, the application-level locks are removed once the timeout for the application is reached. Locks are cleaned up as part of the application un-registration, and thus will time out automatically as part of the application timeout. An application may time out before its session; however, when the session times out, all of its applications are un-registered.

The following list defines every field available in the locks (md_lock) 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.

• Last Access Time - the last date and time the user accessed a given record. If the record is not accessed within the defined timeout value (which is set to 2 hours by default), the lock record is removed automatically by the system. This is done by the thread that is launched when the application server starts up and that is used to monitor for expired sessions.

• Lock ID - the unique identifier for a given lock record. The corresponding transaction table record will have a lock ID column that points to this value.

• Session Application ID - the unique identifier for a given session application.

• Session ID - the unique identifier for a given session ID.

• Date Created - the date the user first created the lock record. Displays the date and time.

• Transaction - an expression column that provides you with the details of a given transaction lock.
  • When personalized in the results section of a view's Search page, this provides the ability to preview the information.

  • When personalized in the Details page, the details are embedded within the page.

• View Name - the name of the view that was being used when the lock was applied.

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