db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Daniel John Debrunner <...@apache.org>
Subject Re: Collation implementation WAS Re: Should COLLATION attribute related code go in BasicDatabase?
Date Thu, 15 Mar 2007 16:00:00 GMT
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?

Thanks,
Dan.


Mime
View raw message