Fuzzy search

Rails
1

This may be offtopic to Rails, but what are people doing to find records
based on fuzzy string matches? For example, if you wanted to find a
Person with name “David Heinemeier H.” but searched using the
string “Dave Hansson”.

Currently I am find_by_sql that calls the PostgreSQL function
“levenshtein(string1, string2)” which returns results with a score
indicating how close the matches are. It is OK, but nowhere good as I
would hope. Any better suggestions?

thanks,
Jeff

2

Am 20.06.2006 um 00:02 schrieb Jeff C.:

Currently I am find_by_sql that calls the PostgreSQL function
“levenshtein(string1, string2)” which returns results with a score
indicating how close the matches are. It is OK, but nowhere good as I
would hope. Any better suggestions?

Try to use a full text index of the database of your choice. Another
thing you might want to try is:

“Search Word”

=> ‘text ILIKE “%SEARCH%” OR text ILIKE “%WORD%”’

Beyond that (sophisticated and prewritten or simple and slow) it
becomes a bit … harder. “Good Text Searching” (“Information
Retrieval” is the academic term which is a bit more general) is one
of the not-yet-completely-solved problems of today’s computer sciences.

Regards,

Manuel

–
I have found an elegant and short solution for Fermat’s Theorem
but sadly there is not enough space for it in this signature.

3

Hi Jeff,

you might want to look at ferret: http://ferret.davebalmain.com as well.
There is a link to the API and in the QueryParser
http://ferret.davebalmain.com/api/classes/Ferret/QueryParser.html you’ll
find an explanation how to build a FuzzyQuery. When you need superfast
search on loads of records you’ll find that sooner or later you’ll need
a
‘search specialist’ in your application anyway…

Regards
Jan