db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: Collation implementation WAS Re: Should COLLATION attribute related code go in BasicDatabase?
Date Thu, 15 Mar 2007 17:22:33 GMT


Daniel John Debrunner wrote:
> Rick Hillegas wrote:
> 
>> Daniel John Debrunner wrote:
>>
>>> ...
>>>
>>> - The collation type (the integer) is written into the meta-data for 
>>> an index just as ascending/descending is today (including the btree 
>>> control row, thus making the information available for recovery). 
>>> Collation type applies to all character columns in the index.
>>>
>> This suggests that all of the columns in the index must have the same 
>> collation? I don't think that is powerful enough to support the 
>> full-blown SQL collation language, which allows you to mix differently 
>> collated columns in an ORDER BY clause. Why can't the collation type 
>> be an array of ints just as the sort direction is an array of booleans 
>> in IndexDescriptor?
> 
> 
> That would be more flexible, but is it required? Is an order by that 
> spills to disk implemented using a BTREE?

No, order by that spills to disk is implemented by the sorter.

> 
> Thanks,
> Dan.
> 
> 
> 


Mime
View raw message