From: | Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr> |
---|---|
To: | Jeff Davis <pgsql(at)j-davis(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Range Types, discrete and/or continuous |
Date: | 2010-10-31 20:42:34 |
Message-ID: | m2wroy856t.fsf@2ndQuadrant.fr |
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Lists: | pgsql-hackers |
Jeff Davis <pgsql(at)j-davis(dot)com> writes:
> Also, there's a good case for continuous ranges for types like NUMERIC,
> but still continuous ranges don't seem quite as important overall.
Well it seems to me that the prefix_range type is continuous, so I would
tend to disagree here :)
A prefix_range is currently written as e.g. '012[3-5]' but could be
worked out to be represented '0123-0125'. In any case here are some
example of values that are contained in the mentioned range:
0123
0124
012345
0123456789
0125221956
You get the idea, I suppose. The main use case is telephony routing:
searching for a prefix in your operator table when you know the phone
number that's calling you.
So let's not forget about continuous ranges, because there's at least
one real-world case that needs them. Oh and it's based on text really,
not on numbers, so that could be the range 'abc-abe'.
I'm too tired to try to understand how your proposal fits with what
would be needed to cover prefix ranges tonight, but I wanted to share
the use case at least.
Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
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