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 o will be translated into different MIL-Expressions at different times? o This question seems more related with operation( // , self-or-descendant).
* Q2: How should i consider execution cost of XPath? o I.E 1: doc("flat.xml")//entry[@rdn='uid=user.301']
+ like one single stair-case-join? + Test result: Need *less *time for execution
o 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. o For small XML less levels will achieve better performance? o For big XML more levels will achieve better performance? o 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