John D. Burger wrote:
> Stephane Bortzmeyer wrote:
>
>> But he can write one in PostgreSQL quite easily. Rational numbers are
>> always the first exercice in CS courses about Abstract Data Types :-)
>
> It's a little tricky to get good performance for all the operations:
>
>> The addition and subtraction operations are complex. They will require
>> approximately two gcd operations, 3 divisions, 3 multiplications and
>>
[..trimed]
>
> (From the Booost rational package -
> http://www.boost.org/libs/rational/rational.html)
>
> I'd try to link to an existing library that provides rationals, or model
> my code closely after one.
>
Yes, it may be easy to create composite type but the operands would
still be needed.
Select n FROM t WHERE frac1 < frac2;
John, do you how compatible the Booost license is (or can be made :-)
with PG, in the case where adding this to the server as a standard
datum-type might be very useful (for me anyway).
Ken
PS - Sorry for the re-send with-the-list, John