Filter by is a mobile business object (MBO) setting, defined during MBO development and used during synchronization of a device application, that allows a subset of data to be returned to the device based on the value specified as the filter.
Filtering by a mapped attribute does not affect the Enterprise Information System (EIS) interaction with Unwired Server. Instead it restricts the rows transferred from the consolidated database (CDb) to the client database to match values the client provides (or retrieved from the default value or personalization key value when the client does not provide a value).
On the Parameters page of the Detailed properties dialog, if you select the Filter by checkbox for a parameter, the value is supplied by the client each time it synchronizes the mobile business object. During a subsequent synchronization, the client may provide different values for the parameter and this affects the Enterprise Information System (EIS) data refresh results that Unwired Server performs.
For example, an MBO has a parameter named CustomerID. The first time a client synchronizes, it passes a value of 000123, and refreshes the MBO and consolidated database (CDb) data for customer 000123. The next time the client synchronizes, the value 004321 is passed. The Sybase Unwired Server refreshes customer data for 004321 from the EIS and then downloads changes for both 000123 and 004321 to the client. If 000123 had happened to change, and the server noticed it for other reasons, than the current synchronization request, then the 000123 data may change. Essentially, when this checkbox is checked, the server remembers all the values you have ever used to synchronize this MBO and attempts to keep the client's copy of all of associated data up-to-date. The client has an ever growing subscription to various horizontal subsets of the MBO data.
If the Filter by checkbox is not checked, the client CDB contains data for only the last value that was synchronized. Using the example, when you synchronize 004321, Sybase Unwired WorkSpace inserts all 004321 data and at the same time deletes all previous 000123 data from the remote database on the device. The client gets a rolling subscription to just the horizontal subset of MBO data based on their last synchronization.