Re: relational tables and objects

From: Jan Hidders <hidders_at_REMOVE.THIS.uia.ua.ac.be>
Date: 2 Nov 2002 10:06:33 +0100
Message-ID: <3dc39599$1_at_news.uia.ac.be>


Dm. Arapov wrote:
>
>"Jan Hidders" <hidders_at_REMOVE.THIS.uia.ua.ac.be> wrote in
>
>> Who receives the 'join' message? I mean, if I join A and B do I say
>>
>> A.join(B)
>>
>> or
>>
>> R.join(A,B)
>
>Neither. The simpliest way to join tables is to call
>join_eq<list_of_columns_to_be_equal>(A,B);

Ok. So query optimization is going to be a matter of letting this function decide on the basis of the types what algorithm it is going to use? That's not really open-ended (it cannot take new table types into account without changing this function) but I don't see a way to do that anyway.

>Result of this call will be object of class join_t_eq<TableA, TableB,
>list_of_columns_to_be_equal>.

Interesting. Why is the list of columns in the type? And if I do join(A,join(B,C)) will the result have the same type as join(join(A,B),C) or not? So can you statically type the set union?

  • Jan Hidders
Received on Sat Nov 02 2002 - 10:06:33 CET

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