On 29.01.2016 18:39, Alvaro Herrera wrote:
Teodor Sigaev wrote:
The behavior of this function is surprising to me.
select substring_similarity('dog' , 'hotdogpound') ;
substring_similarity
----------------------
0.25
Substring search was desined to search similar word in string:
contrib_regression=# select substring_similarity('dog' , 'hot dogpound') ;
substring_similarity
----------------------
0.75
contrib_regression=# select substring_similarity('dog' , 'hot dog pound') ;
substring_similarity
----------------------
1
Hmm, this behavior looks too much like magic to me. I mean, a substring
is a substring -- why are we treating the space as a special character
here?
I think, I can rename this function to subword_similarity() and correct
the documentation.
The current behavior is developed to find most similar word in a text.
For example, if we will search just substring (not word) then we will
get the following result:
select substring_similarity('dog', 'dogmatist');
substring_similarity
---------------------
1
(1 row)
But this is wrong I think. They are completely different words.
For searching a similar substring (not word) in a text maybe another
function should be added?
--
Artur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company
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