Release 10.1A: OpenEdge Development:
Progress Dynamics Advanced Development

Enabling SDO-level caching

SDO-level caching improves on SDF-level caching in some situations. When the following behavior is desired or improves performance, use SDO-level caching:

When visual objects that are not combo boxes can also use the data.
When combo boxes with different list formatting can use the same data.
When the initial retrieval of data must be done in the same AppServer hit as the rest of the data in the container. (A single lookup in a viewer will negate the reduction of Appserver hits.)
When you need SDO behavior like calculated fields or temp-table support, and so on.

The main difference with SDO-level caching is that the dynamic combo list (list-item-pairs) must be built each time a dynamic combo is instantiated. SDF-level caching builds this list on the server and caches the list. Each instance then copies the list exactly. Using an SDO-level cache data incurs a slight overhead since it must build the list for each instance at start up.

To set SDO-level caching:

Select Build Smart Data Field Maintenance, as shown:



From the Data source option button, select DataObject. The Query section is disabled and the SDF Maintenance tool enables the DataObject name field.
Note: When changing an existing dynamic combo from a database query to an SDO, the tool attempts to retain the fields displayed and key field of the dynamic combo. It removes the table name qualifier from the fields displayed and from the key field and attempts to find matching columns in the SDO. If it finds matching columns, it uses those. If it does not find matching columns, it discards the query source data. When changing from an SDO data source to a database query, the tool makes no attempt to retain the fields displayed or the key field of the dynamic combo.
Enter the SDO name in the DataObject name field. When you enter a valid SDO, the tool updates the field list below to display the columns of the selected SDO. The Key field combo box contains the columns of the selected SDO.
Unselect the Use cache option. For an explanation of what occurs when Use cache is enabled with DataObject selected, see the next section.
Save and exit.