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Re: array support patch phase 1 patch

From: Joe Conway <mail(at)joeconway(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Patches (PostgreSQL)" <pgsql-patches(at)postgresql(dot)org>
Subject: Re: array support patch phase 1 patch
Date: 2003-06-01 00:14:47
Message-ID: 3ED94577.5010801@joeconway.com (view raw or flat)
Thread:
Lists: pgsql-patches
Tom Lane wrote:
> Another problem is:
> 
> regression=# select distinct array(select * from text_tbl) from foo;
> ERROR:  Unable to identify an equality operator for type text[]
> 
> This DISTINCT query would fail anyway of course, for lack of a '<'
> operator for arrays, but it seems like we ought to be able to find the
> polymorphic '=' operator.

The attached small patch addresses the above concern (finding 
polymorphic "=" operator) by introducing a new function, 
IsPolymorphicCoercible().

Now, as predicted, I get:

regression=# select distinct array(select f1 from tse);
ERROR:  Unable to identify an ordering operator for type integer[]
         Use an explicit ordering operator or modify the query

If there are no objections, please apply.

Next question this begs is, should I work on a '<' operator for arrays? 
And if so, how is the behavior defined? Hannu suggested 
element-by-element, analogous to character-by-character text string 
comparison. Comments?

Thanks,

Joe

Attachment: array-polycoerce.1.patch
Description: text/plain (2.8 KB)

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Subject: Re: [HACKERS] Are we losing momentum?
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Subject: array support phase 3 patch (was Re: array support patch phase 1 patch)

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