The XQuery Expression Editor
This page last changed on Nov 28, 2008.
Oracle Data Service Integrator Documentation > Data Services Developer's Guide How To Edit XQuery ExpressionsThis topic describes how to edit XQuery expressions in the expression editor in Workshop for WebLogic. OverviewYou can edit the generated XQuery expressions in an update map using the expression editor. The Expression Editor in an Update MapThe update map expression language is a subset of XQuery syntax. In an update map, you can use any of the following XQuery constructs.
Namespace prefixes are declared in the data service's XQuery source, which you can see in the Source tab. If a namespace is only used in the update map, and not in the logical data service, you must declare it. If a namespace cannot be resolved, it is shown with the prefix ns?. The most common ways you use the expression editor are to:
The fn-bea:value FunctionA mapping between an element in a return type and an element in an update block uses the fn-bea:value function with a path name, for example: fn-bea:value($CUSTOMER/CUSTOMER_ID) An update mapping should always use fn-bea:value, whether Oracle Data Service Integrator auto-generates the mapping or you draw it. If you remove the fn:bea:value function from the expression and simply use an XQuery path expression ($CUSTOMER/CUSTOMER_ID), the element becomes disabled in the update map and you see this error message: The expression does not match the expected type for this element The fn-bea:value function is required, because an update map updates a Service Data Object (SDO) and requires a special XML structure called a datagraph that includes a change summary showing both the old and new values. The fn-bea:value function handles the update to the SDO correctly. If you do not use fn-bea:value, Oracle Data Service Integrator throws an exception when you attempt to update the value.
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