[HACKERS] SQL/MED spec for cross-database linkages
Joe, have you heard of a standard called SQL/MED? I came across a description of it the other day. You might think it's got some medical connotation, but actually the acronym is Management of External Data, and what it is is a standard spec for shipping chunks of SQL queries to remote servers. For instance, given SELECT * FROM a.foo, b.bar WHERE ... where a.foo is on a remote machine, the spec lays down how the local and remote servers can cooperate to execute this query intelligently --- including deciding where to execute various WHERE clauses to minimize the amount of data shipped. (The article I found was actually about how the new draft version of SQL/MED improves the protocol to let this sort of thing be done better; it seems the original spec only allowed retrieval of a whole table's contents.) This looks like it might be a great long-term replacement for dblink, and if it is standard, so much the better. I imagine the draft version of the new SQL/MED spec may be available on the web, but haven't gone looking. Just a heads-up in case you are interested... regards, tom lane ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [HACKERS] SQL/MED spec for cross-database linkages
On Fri, 2002-12-06 at 11:04, Tom Lane wrote: Joe, have you heard of a standard called SQL/MED? I came across a It's that one of the later parts of the SQL 99 spec? Section 9 or thereabouts? -- Rod Taylor [EMAIL PROTECTED] PGP Key: http://www.rbt.ca/rbtpub.asc signature.asc Description: This is a digitally signed message part
Re: [HACKERS] SQL/MED spec for cross-database linkages
On Fri, 2002-12-06 at 11:35, Rod Taylor wrote: On Fri, 2002-12-06 at 11:04, Tom Lane wrote: Joe, have you heard of a standard called SQL/MED? I came across a It's that one of the later parts of the SQL 99 spec? Section 9 or thereabouts? Note to self, don't reply to emails and have a separate conversation at the same time. Found SQL/MED, Section 21 of ISO 9075-9. -- Rod Taylor [EMAIL PROTECTED] PGP Key: http://www.rbt.ca/rbtpub.asc signature.asc Description: This is a digitally signed message part
Re: [HACKERS] SQL/MED spec for cross-database linkages
Tom Lane wrote: Joe, have you heard of a standard called SQL/MED? I came across a description of it the other day. You might think it's got some medical connotation, but actually the acronym is Management of External Data, and what it is is a standard spec for shipping chunks of SQL queries to remote servers. For instance, given SELECT * FROM a.foo, b.bar WHERE ... where a.foo is on a remote machine, the spec lays down how the local and remote servers can cooperate to execute this query intelligently --- including deciding where to execute various WHERE clauses to minimize the amount of data shipped. (The article I found was actually about how the new draft version of SQL/MED improves the protocol to let this sort of thing be done better; it seems the original spec only allowed retrieval of a whole table's contents.) This looks like it might be a great long-term replacement for dblink, and if it is standard, so much the better. Great! Thanks for the heads up. I see that Rod provided the reference in his post -- I'll go find it. The idea of expanding dblink to other RDBMSs is picking up steam. I've been conversing off list with someone who has a semi-working hacked version of dblink that uses JDBC in place of libpq. Do you think a proposal based on the SQL/MED spec would be entertained for 7.4, or would the release after be a safer bet? I'm not sure (since I haven't seen it yet) what I'm getting myself into ;-), but I might like to take it on since there seems to be a lot of interest. Joe Joe ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [HACKERS] SQL/MED spec for cross-database linkages
Rod Taylor [EMAIL PROTECTED] writes: Found SQL/MED, Section 21 of ISO 9075-9. That's the old version, though. The new draft is at (digs out article) http://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-14-XML-2002-03.pdf according to this article, but I'm not having any luck accessing that URL. Let me email the authors and see if I can get a copy. regards, tom lane ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] SQL/MED spec for cross-database linkages
Joe Conway [EMAIL PROTECTED] writes: Do you think a proposal based on the SQL/MED spec would be entertained for 7.4, or would the release after be a safer bet? The impression I get from this article is that SQL/MED is nontrivial. If you think you can get something useful going for 7.4, step right up --- but I think you should plan on being at it for awhile. In any case, a multi-step implementation plan would be a good idea. regards, tom lane ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] SQL/MED spec for cross-database linkages
On Fri, Dec 06, 2002 at 01:52:01PM -0500, Tom Lane wrote: Rod Taylor [EMAIL PROTECTED] writes: Found SQL/MED, Section 21 of ISO 9075-9. That's the old version, though. The new draft is at (digs out article) http://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-14-XML-2002-03.pdf according to this article, but I'm not having any luck accessing that URL. Let me email the authors and see if I can get a copy. Hmm, seems you need to change protocols: ftp://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-14-XML-2002-03.pdf Ross ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [HACKERS] SQL/MED spec for cross-database linkages
On Fri, Dec 06, 2002 at 01:52:01PM -0500, Tom Lane wrote: Rod Taylor [EMAIL PROTECTED] writes: Found SQL/MED, Section 21 of ISO 9075-9. That's the old version, though. The new draft is at (digs out article) http://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-14-XML-2002-03.pdf according to this article, but I'm not having any luck accessing that URL. Let me email the authors and see if I can get a copy. regards, tom lane ---(end of broadcast)--- TIP 6: Have you searched our list archives? Having pulled that one, I discover it's actually the XML related spec. The MED one is at: ftp://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-09-MED-2002-01.pdf There's a text version, as well (always nice for grepping): ftp://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-09-MED-2002-01.txt Ross ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [HACKERS] SQL/MED spec for cross-database linkages
Ross J. Reedstrom [EMAIL PROTECTED] writes: Having pulled that one, I discover it's actually the XML related spec. The MED one is at: ftp://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-09-MED-2002-01.pdf Ah-hah, so the URL in the SIGMOD Record article is just wrong :-( Meanwhile, one of the authors sent me a copy privately (it helps to have shared an office at grad school ;-)) which I was about to offer around, but I guess we can just use the FTP link instead. regards, tom lane ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html