You can perform connected (online) or disconnected (offline) updates of records from PDA or BlackBerry client applications. The Mobile Application Development Tutorial includes instructions for performing an update.
Having multiple copies of the same data on multiple mobile devices on which multiple users can update and perform sync operations introduces the problem of one user’s updates cancelling modifications made by other users. Unwired Accelerator provides concurrency control and conflict resolution to solve this problem.
When you make changes on record data from your PDA device while running applications in disconnected mode, you can check the status of your update operation. You can confirm whether the update operation succeeded, and if not, you can find out why it failed. The Mobile Portal Server maintains a log of all update requests it receives from the M-Business server during sync operations. Logs are created in the portaldatabase.
When you perform sync operations, update logs are sent to the PDA device. Click Log in the application pages to see a list of all sync log records. The List page of the logs shows only a subset of the fields from the log record. To see more details, click any column of the log record to display the detail page.
Use the Delete button on the detail page to delete log records. Delete log records periodically, otherwise, the list grows and increases your sync times. When you delete a log record, it is immediately removed from the device database and no longer appears in the log record list. However, the records are not deleted from the portal server until the next sync operation.
Unwired Accelerator uses optimistic concurrency control. This allows users to make changes to records on their local devices, but at sync time, the mobile portal server rejects an update operation if the data submitted for modification has already been modified by another user in the enterprise. For example, if four users change the same record and perform the sync operation, only the first user’s sync is executed, and the other three users’ update requests are rejected.
During sync, the PDA devices return the original value (the value before the change) of the updated record columns, the new value for the columns, and all the search parameter values defined in the updated application, to the linked application of the mobile portal server. See “Creating update links (with conflict resolution)”.
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