问题
I have couple of documents on which xdmp:node-replace() over certain elements doesnot work. There are some other set of documents which are almost similar to the ones that has problem but xdmp:node-replace works perfectly fine on them. Tried all possibilities that could have gone wrong but in vain. Read some where that xdmp:node-replace function does not work on 'in memory elements'.
So in order to verify whether the issue is with 'in memory elements', I want to know what exactly it is.
Any light on it would be of great help
回答1:
Anything constructed within a query is an in-memory element. For example this XQuery yields an in-memory element:
<test/>
Some function calls also return in-memory elements: xdmp:unquote is an obvious example. Any node that doesn't come from the current database will be treated as an in-memory node.
This query yields a database element (if it exists), which could be modified using xdmp:node-replace:
doc('fubar')/test
This is a typical in-memory update error:
xdmp:node-replace(<x/>, <y/>)
With MarkLogic 6.0-1.1, the error code is XDMP-UPCONSTNODES.
回答2:
If you want to update in-memory nodes as if they were in the database by using similar function calls, there's a utility library that does that:
https://github.com/marklogic/commons/tree/master/memupdate
The main library also ships with MarkLogic Server under App Services:
appservices/utils/in-mem-update.xqy
回答3:
If your working with in memory elements import the following module
import module namespace mem = "http://xqdev.com/in-mem-update" at "/MarkLogic/appservices/utils/in-mem-update.xqy";
Instead of using xdmp:node-replace you can use mem:node-replace(<x/>, <y/>)
来源：https://stackoverflow.com/questions/13583130/what-are-in-memory-elements-in-marklogic