Hi,
thx for all your kind answers. I also find this feature is actually
well documented in:
http://monetdb.cwi.nl/MonetDB/Version4/Documentation/monet/index.html
As deprecated at website, i have never paid attention to these staffs.
For those who use MonetDB/XQuery,
that may really helpful, at least to be noticed the existence of these
documentations.
Old problems solved and new questions appear. The mention XML-files
flat.xml and deep.xml are send with this mail.
Both file have the some content but different structure. flat.xml with
less levels and deep.xml with more levels.
- Q1: XPath/XQuery will be translated in MIL-Expressions, is the
translation deterministic? I mean, can this happen that the same input
of XPath/XQuery
- will be translated into different MIL-Expressions at different
times?
- This question seems more related with operation( // ,
self-or-descendant).
- Q2: How should i consider execution cost of XPath?
- I.E 1:
doc(\"flat.xml\")//entry[@rdn='uid=user.301']
- like one single stair-case-join?
- Test result: Need less time for execution
- I.E 2:
doc(\"flat.xml\")/dsml/directory-entries/entry[@rdn='uid=user.301']
- like some nested normal selections?
- Test result: Need more time for execution
- Q3: Is that possible to get translated MIL-Expressions of
XPath/XQuery?
- Q4: About design of XML. Is there any trade-off-rules, that
should be considers with structure design of XML.
- For small XML less levels will achieve better performance?
- For big XML more levels will achieve better performance?
- Test result with flat.xml and deep.xml: ( The difference i
found, any explanations? )
- from deep.xml: [ "1000000016_vx_hsh_nid", "int",
"oid", 1726, 0, "clean", "load", "pers", 0,
1 ]
- from flat.xml: [ "1000000017_vx_hsh_nid", "int",
"oid", 825, 0, "clean", "load", "pers", 0,
1 ]
So far get so much confused points, hope some experts can give me a
hint.
Best regards,
Chaojing
--
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Email: chaojing.yang@gmail.com
Blog: http://goethe-ist-taoist.blogspot.com/
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