So one reason to do this, in the example given, is that (hypothetically) a city field in an address might have:
HOUSTON, houston, Houston, HOuston, etc. Rather than using a computed field, you would use a case insensitive, maybe whitespace and punctuation insensitive index, so NEW YORK NEW YORK New YORK New York new york etc, would all be considered ‘equal.’ in terms of the index. While this doesn’t cover every instance where you might want a function index, it handles those cases where you’re worried about the case of the text, punctuation, or spaces. > On Jan 8, 2015, at 2:47 PM, Alexei Betin <[email protected]> wrote: > > Hello, > > Does MarkLogic has something similar to “function index” as exists in other > databases such as Oracle? For example, in Oracle one can create a function > index on a value of UPPER(<field_name>) as follows: > > CREATE INDEX cities_fn_idx ON cities (UPPER(name)); > which ensures that a query like the one below is efficient and not using the > full table scan: > SELECT name FROM cities WHERE UPPER(name) = 'HOUSTON'; > > I’d like to do something similar with MarkLogic which could help speed up, > e.g. the following simple query (which currently runs prohibitively slow > despite an index on /A/City): > > collection()/A/[upper-case( City ) = 'HOUSTON'] > > upper-case() is only an example, I am looking for a solution that would > accommodate any function/transformation that derives a value to be used in a > query condition from an existing element. > > Clearly, one solution would be to pre-compute the derived field, add it to > all the documents in the collection, and create an index on the derived field > – this is possible, but I want to make sure I am not missing a solution that > does not require data modification (such as a “function index”). > > Thanks, > > <image005.jpg> > <image006.jpg> > Alexei Betin > Principal Architect; Big Data > P: (817) 928-1643 | Elevate.com <http://www.elevate.com/> > 4150 International Plaza, Suite 300 > Fort Worth, TX 76109 > > Privileged and Confidential. This e-mail, and any attachments thereto, is > intended only for use by the addressee(s) named herein and may contain > privileged and/or confidential information. If you have received this e-mail > in error, please notify me immediately by a return e-mail and delete this > e-mail. You are hereby notified that any dissemination, distribution or > copying of this e-mail and/or any attachments thereto, is strictly > prohibited. > > _______________________________________________ > General mailing list > [email protected] <mailto:[email protected]> > http://developer.marklogic.com/mailman/listinfo/general > <http://developer.marklogic.com/mailman/listinfo/general>
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