not surprisingly, the db2 approach is the only one that seems to follow the "ideal" of the relational dbms. looks like you get to provide to the engine information about your data, rather than describing to the engine what steps it's supposed to take. hints that directly influence query plans seem like a huge step backwards. if you want tight control over what the engine does you use a pure rules based (rather than cost based) optimizer. but nobody (including sqlite) does that anymore for good reasons.
On Sep 21, 2008, at 12:59 PM, Stephen Woodbridge wrote: > D. Richard Hipp wrote: >> On Sep 21, 2008, at 8:51 AM, Russ Leighton wrote: >> >>> I am interested in ... a way >>> to constraint/control index selection on queries. >>> >> >> What other SQL database engines have this capability and what syntax >> do they use? > > Richard, > > Hope this are useful: > > Oracle: > http://www.adp-gmbh.ch/ora/sql/hints/index.html > http://download.oracle.com/docs/cd/E12096_01/books/admintool/ > admintool_PhysicalSetup32.html > > Postgresql: > Does not support it unless it is a very recent addition, but its > planner > occasionally/frequently? makes a poor choice and adding support for > hints ala Oracle and/or discussions like "Why didn't Postgresql use my > index?" regularly occur on the user list. > > DB2: > http://publib.boulder.ibm.com/infocenter/db2luw/v8/index.jsp?topic=/ > com.ibm.db2.udb.doc/admin/t0005308.htm > > MySQL: > http://dev.mysql.com/doc/refman/5.0/en/index-hints.html > > -Steve > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
