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Problems in Schema-aware Xquery
Added by Anonymous over 15 years ago
Legacy ID: #7475237
Legacy Poster: Sudhir (sudhirdumbre)
Thank you for ur last reply to thread "Finding Xqueries using wrong
xpath". As per our last conversation i have changed the (basic)Configuration to
SchemaAwareConfiguration. But still we are not able to track the errors in the XPath
expression. For example:Consider the books.xml <Q
xsi:noNamespaceSchemaLocation="books.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<BOOKS> <ITEM CAT="MMP">
<TITLE>Pride and Prejudice</TITLE>
<AUTHOR>Jane Austen</AUTHOR> <PUBLISHER>Modern
Library</PUBLISHER>
<PUB-DATE>2002-12-31</PUB-DATE>
<LANGUAGE>English</LANGUAGE>
<PRICE>4.95</PRICE>
<QUANTITY>187</QUANTITY>
<ISBN>0679601686</ISBN>
<PAGES>352</PAGES> <DIMENSIONS
UNIT="in">8.3 5.7 1.1</DIMENSIONS> <WEIGHT
UNIT="oz">6.1</WEIGHT> </ITEM>
</BOOKS> <CATEGORIES DESC="Miscellaneous
categories"> <CATEGORY CODE="P"
DESC="Paperback"/> </CATEGORIES>
</Q> And the following xquery which just compares the quantity value and
pages value. Also note the Xpath for locating the node ITEM is
incorrect"//BOOKS/IT".As per my requirement i want to track such
errors using schema-aware Saxon. import schema default element namespace
"" at "com/xqueries/books.xsd"; for $item in
//BOOKS/IT return( if(fn:number($item/QUANTITY) < fn:number($item/PAGES)) then (
<Param>Correct Data</Param> ) else (
<Param>InCorrect Data</Param> ) ) And java code used is as
follows: final SchemaAwareConfiguration config = new SchemaAwareConfiguration(); final
StaticQueryContext sqc = new StaticQueryContext(config); final XQueryExpression exp =
sqc.compileQuery(new FileReader("books.xquery"));
Legacy ID: #7475424
Legacy Poster: Michael Kay (mhkay)
Saxon will give you a compile-time warning (not an error, because it isn't an error)
if it can determine at compile time that a path expression will select nothing. For
this, you have to declare what type of document the query is expected to process. I
usually do this by writing: declare variable $input as document-node(schema-element(Q))
:= .; for $item in $input//BOOKS/IT .... This also has the effect that you will get a
run-time error if you supply the wrong kind of input document, or if the input document
has not been validated. Note that in your Java code you should also set
config.setSchemaValidation(Validation.STRICT) to ensure that the input document is
validated against the schema.
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