How to get xml attribute using Apache Derby

[Grzegorz Zuber]

Hi,

How to get xml attribute using Apache Derby?

I was doing it like this, but it's not working.


I've created table using:

create table xml_orders (xml_col xml)

Then I inserted value to its doing:

INSERT
INTO
   xml_orders
VALUES
   (      XMLPARSE(DOCUMENT '
<orders>
 <singleOrder no="1" date="2015-01-22">
 </singleOrder>
</orders>
'PRESERVE WHITESPACE) )


But when I'm doing query like this:


SELECT XMLSERIALIZE(

        XMLQUERY('//singleOrder/@date' PASSING BY REF xml_col EMPTY ON

        EMPTY) AS VARCHAR(1000)

    )AS CustomerId

FROM xml_orders



I'm getting error:


Caused by: ERROR 2200W: XQuery serialization error: Attempted to
serialize one or more top-level Attribute nodes.
        at org.apache.derby.iapi.error.StandardException.newException(Unknown 
Source)
        at org.apache.derby.iapi.error.StandardException.newException(Unknown 
Source)
        at org.apache.derby.iapi.types.XML.XMLSerialize(Unknown Source)
        at 
org.apache.derby.exe.ac23ffc05bx0150xf290x866cx000006bfe7900.e0(Unknown
Source)
        at org.apache.derby.impl.services.reflect.DirectCall.invoke(Unknown 
Source)
        at 
org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.doProjection(Unknown
Source)
        at 
org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.getNextRowCore(Unknown
Source)
        at 
org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.getNextRow(Unknown
Source)
        ... 38 more



Thank you,
Greg