Обсуждение: SQL/XML extension
Dear PostreSQL hackers, For the interested, here: http://www.cs.utwente.nl/~hiemstra/courses/reports/sqlxml.pdf you find a little report discussing possibilities to implement the SQL/XML standard using the PostgreSQL extension mechanism. The report is written by Master students following the course "XML & Databases" at U Twente. Comments are welcome. (I am not on the developers list, so please reply to my personal email as well) Best regards, Djoerd. -- Djoerd Hiemstra University of Twente Department of Computer Science PO Box 217, 7500 AE Enschede, The Netherlands URL: www.cs.utwente.nl/~hiemstra Tel: +31 53 4892335
Djoerd, > http://www.cs.utwente.nl/~hiemstra/courses/reports/sqlxml.pdf > you find a little report discussing possibilities to implement the > SQL/XML standard using the PostgreSQL extension mechanism. The report is > written by Master students following the course "XML & Databases" at U > Twente. Comments are welcome. (I am not on the developers list, so > please reply to my personal email as well) Cool, thanks! Is this something that somebody is actually working on, or just the paper? -- Josh Berkus Aglio Database Solutions San Francisco
Paul, Rob, I just read with some interest your paper on XML queries with PostgreSQL. I'm particularly puzzled by some of your conclusions, and thought you might want to discuss them with the PGSQL-Hackers mailing list. Particulary: Functions should be able to have a variable amount of arguments. I find this conclusion odd, because function overloading (that is, the idea that a function is defined by the combination of its name and the number and type of arguments) is now enshrined in the SQL2003 standard. Of course, I wouldn't be at all surprised to find out that the SQL committee had broken their own standard. ;-) Re-defining AS would, as you notice, break many things. However, you could easily get around this through quoting. While that would not be exactly adherent to the standard, it's easier that re-writing the parser. In some ways, it seems to me that SQL/XML might be better defined as a separate interface to the database; that is, it's own "shell" which is incompatible with SQL (since the committee seems to have deliberately made it incompatible). Thoughts? -- Josh Berkus Aglio Database Solutions San Francisco
I'm thinking about GiST approach http://www.cs.arizona.edu/xiss/ Oleg On Thu, 18 Aug 2005, Djoerd Hiemstra wrote: > Dear PostreSQL hackers, > > For the interested, here: > http://www.cs.utwente.nl/~hiemstra/courses/reports/sqlxml.pdf > you find a little report discussing possibilities to implement the SQL/XML > standard using the PostgreSQL extension mechanism. The report is written by > Master students following the course "XML & Databases" at U Twente. Comments > are welcome. (I am not on the developers list, so please reply to my personal > email as well) > > Best regards, > Djoerd. > > Regards, Oleg _____________________________________________________________ Oleg Bartunov, sci.researcher, hostmaster of AstroNet, Sternberg Astronomical Institute, Moscow University (Russia) Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/ phone: +007(095)939-16-83, +007(095)939-23-83
IIRC, Peter Eisentraut noted a while ago that implementing the SQL/XML functions properly would require building them into the postgresql parser as special cases. That of course would mean we wouldn't be using the extension mechanism, and is something we should normally shy away from, but I think it could be contemplated for something that is in the standard. The paper does not seem to have addressed the issue of how this could be done other than bu using the extension mechanism - that seems a bit of a pity, although maybe that's exactly the topic they were set. cheers andrew Josh Berkus wrote: >Paul, Rob, > >I just read with some interest your paper on XML queries with PostgreSQL. >I'm particularly puzzled by some of your conclusions, and thought you might >want to discuss them with the PGSQL-Hackers mailing list. > >Particulary: >Functions should be able to have a variable amount of arguments. > >I find this conclusion odd, because function overloading (that is, the idea >that a function is defined by the combination of its name and the number and >type of arguments) is now enshrined in the SQL2003 standard. Of course, >I wouldn't be at all surprised to find out that the SQL committee had broken >their own standard. ;-) > >Re-defining AS would, as you notice, break many things. However, you could >easily get around this through quoting. While that would not be exactly >adherent to the standard, it's easier that re-writing the parser. > >In some ways, it seems to me that SQL/XML might be better defined as a >separate interface to the database; that is, it's own "shell" which is >incompatible with SQL (since the committee seems to have deliberately made it >incompatible). > >Thoughts? > > >
Dear Josh and Andrew, Thanks for the prompt replies. For now it's just a paper. It was Rob and Pim's mission to find out if the SQL /XML standard can be implemented using the postgresql extension mechanism. Building it into the parser was no option. Best, Djoerd. On Thu, 18 Aug 2005, Andrew Dunstan wrote: > > IIRC, Peter Eisentraut noted a while ago that implementing the SQL/XML > functions properly would require building them into the postgresql > parser as special cases. That of course would mean we wouldn't be using > the extension mechanism, and is something we should normally shy away > from, but I think it could be contemplated for something that is in the > standard. > > The paper does not seem to have addressed the issue of how this could be > done other than bu using the extension mechanism - that seems a bit of a > pity, although maybe that's exactly the topic they were set. > > cheers > > andrew > > Josh Berkus wrote: > > >Paul, Rob, > > > >I just read with some interest your paper on XML queries with PostgreSQL. > >I'm particularly puzzled by some of your conclusions, and thought you might > >want to discuss them with the PGSQL-Hackers mailing list. > > > >Particulary: > >Functions should be able to have a variable amount of arguments. > > > >I find this conclusion odd, because function overloading (that is, the idea > >that a function is defined by the combination of its name and the number and > >type of arguments) is now enshrined in the SQL2003 standard. Of course, > >I wouldn't be at all surprised to find out that the SQL committee had broken > >their own standard. ;-) > > > >Re-defining AS would, as you notice, break many things. However, you could > >easily get around this through quoting. While that would not be exactly > >adherent to the standard, it's easier that re-writing the parser. > > > >In some ways, it seems to me that SQL/XML might be better defined as a > >separate interface to the database; that is, it's own "shell" which is > >incompatible with SQL (since the committee seems to have deliberately made it > >incompatible). > > > >Thoughts? > > > > > > >
"Andrew Dunstan" <andrew@dunslane.net> wrote > > IIRC, Peter Eisentraut noted a while ago that implementing the SQL/XML > functions properly would require building them into the postgresql parser > as special cases. That of course would mean we wouldn't be using the > extension mechanism, and is something we should normally shy away from, > but I think it could be contemplated for something that is in the > standard. > I guess the reason why SQL/XML should be built into the main parser is the same as PL/PGSQL. But how did DB2 make it in an extendor way( http://www-306.ibm.com/software/data/db2/extenders/xmlext/ )? Maybe they have two copies of SQL parser, one has the basic SQL grammar, the other is the basic SQL grammar plus or integrated with XML support, once XML extendor is installed, the basic one will be replaced? Regards, Qingqing
Is there any more XML activity that people are working on this area? --------------------------------------------------------------------------- Djoerd Hiemstra wrote: > Dear PostreSQL hackers, > > For the interested, here: > http://www.cs.utwente.nl/~hiemstra/courses/reports/sqlxml.pdf > you find a little report discussing possibilities to implement the > SQL/XML standard using the PostgreSQL extension mechanism. The report is > written by Master students following the course "XML & Databases" at U > Twente. Comments are welcome. (I am not on the developers list, so > please reply to my personal email as well) > > Best regards, > Djoerd. > > -- > Djoerd Hiemstra > University of Twente > Department of Computer Science > PO Box 217, 7500 AE > Enschede, The Netherlands > > URL: www.cs.utwente.nl/~hiemstra > Tel: +31 53 4892335 > > > ---------------------------(end of broadcast)--------------------------- > TIP 6: explain analyze is your friend > -- Bruce Momjian http://candle.pha.pa.us SRA OSS, Inc. http://www.sraoss.com + If your life is a hard drive, Christ can be your backup. +
Hello, This patch is well, I hope. I didn't look on it half year. Contains: SQL/XML support + doc by D.Fetter http://candle.pha.pa.us/mhonarc/patches_hold/msg00134.html regards Pavel Stehule _________________________________________________________________ Najdete si svou lasku a nove pratele na Match.com. http://www.msn.cz/
Pavel Stehule wrote: > Hello, > > This patch is well, I hope. I didn't look on it half year. Contains: SQL/XML > support + doc by D.Fetter > http://candle.pha.pa.us/mhonarc/patches_hold/msg00134.html Yes, I am just looking at it now. -- Bruce Momjian http://candle.pha.pa.us SRA OSS, Inc. http://www.sraoss.com + If your life is a hard drive, Christ can be your backup. +