Re: Extended unit
От | Pailloncy Jean-Gerard |
---|---|
Тема | Re: Extended unit |
Дата | |
Msg-id | b1ef5d24ec68884f380b5ebf8caa0b9d@rilk.com обсуждение исходный текст |
Ответ на | Re: Extended unit (PFC <lists@boutiquenumerique.com>) |
Список | pgsql-general |
>> ision range you need), but does not allow >> to be added with anything else than "amper". Any other interaction >> with >> other units (read data types) would be achieved by defining the needed >> operators on the respective data types (read units). > > You'd have to create a postgres datatype for every variation on m, > m/s, m/s², etc... which would be kinda unworkable... I think it's > better to have one datatype (number with unit) and have the operators > raise an exception when trying to add incompatible units ? No doable. After you will need the factorial number of operator between all the combinatory of couple of unit. > As for the encoding, why not just use a (float, text) with the text > as a parseable I am doing test with this. But constraint is done at execution time. Space is larger. Operation of two of these is slower than the native one (float). I want to have it at parsing level to speed the error detection as writing code. > representation of the unit, which could as well be the SI unit (like > m/s) which would be a lot more flexible than bitfields. Problem is I > think it'll always be variable length. Maybe there is enough space in > an int64 to fit it all ? Maybe with huffman coding ? Is it really > important to save a few bytes ? I don't think so. (float, text) versus (float) with text is cd3.A2.sr.m-1.s-2.rad-3.kg-4 with an experiment of few milions of results that have few dozen of parameter. just to be sure that be not add at parser time meter with second. I think this work-less, except for a proof of concept. Cordialement, Jean-Gérard Pailloncy
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