Release 10.1A: OpenEdge Development:
Progress Dynamics Administration

Using mapped fields

You can use the mapped field feature when there is a dynamic lookup on a viewer and you must display extra information on the viewer for the selected or displayed lookup record. In this case, you can add a field to the viewer and link this field to a selected field in the lookup browser that displays when a selection is made.

For example, you can modify the CustomerCodeLookup in the order viewer that you build as part of the Progress Dynamics tutorial using the dynsports database. (For more information on this tutorial, see OpenEdge Development: Progress Dynamics Getting Started .) For the tutorial, you create this lookup on the fill-in for the customer object field (customer_obj) that you generate as part of the dynamic viewer (artorviewv) for art_order. For a given order, this lookup displays the customer name that you select from the lookup browser with a query on arm_customer. The lookup browser displays both customer_code and customer_name for each arm_customer, and the lookup also contains a link from customer_balance to a fill-in (fiCustBalance) that you create on the viewer so the balance can be displayed for the selected customer.

Preparing the lookup for field mapping

In the tutorial example, CustomerCodeLookup uses three fields from the query on arm_customer:

customer_balance
customer_code
customer_name

In order to avoid AppServer requests when displaying the fields used by a lookup, you must map all of the fields used in the lookup query to the viewer data source (SDO), including the displayed field, all fields specified for the lookup browser sequence, and any specified linked fields. For this example, you must map the three lookup fields to corresponding fields in the SDO for art_order (artorfullo). Because the tutorial generates the artorfullo SDO as a data source for art_order only, you must explicitly add the arm_customer fields for the lookup to this SDO.

To add the arm_customer fields to the lookup:

Modify the SDO to join art_order to arm_customer (on customer_obj, by default).
Add the fields from arm customer to the SDO like this:
customer_balance — Not updateable.
customer_code — Not updateable.
customer_name — Updateable.

Mapping lookup fields to the SDO

You can map the lookup fields in the following ways:

Linking lookup fields directly to SDO fields on the viewer
Mapping lookup fields to SDO fields through viewer widgets

These two options essentially provide the same results at run time. However, for cases where you cannot use the first option, you can use the second option to get the lookup data from the SDO.

In the example from the tutorial, you can use either option. However, the first option produces a less practical result, with an extra (and redundant) field on the viewer.

Note: Dynamics only uses the field mapping mechanism when records are being displayed from the data source. If the user changes a lookup’s value, the default behavior for retrieving these values (from the AppServer) executes. However, the mechanism still improves performance and reduces AppServer requests.