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From "Mamta Satoor" <msat...@gmail.com>
Subject Re: Collation and parameter markers (?)
Date Tue, 05 Jun 2007 20:53:00 GMT
you are right. Both the sides have the same collation which is UCS_BASIC
since result of CAST picks up the DTD associated with what the operand is
getting CASTed to. Since char(10) has collation type of UCS_BASIC attached
to it, the result of CAST picks up that collation irrespective of collation
of the operand.  I am wondering though if that is what user would expect
when writing a query like following
select * from customer where CAST(? as char(10)) = cast(name as char(10)).
That is UCS_BASIC getting used for comparison rather than territory based
collation.

Mamta



On 6/5/07, Daniel John Debrunner <djd@apache.org> wrote:
>
> Mamta Satoor wrote:
> > I realize that we are still discussing what should be the right
> > collation for different character string type instances, but I want to
> > put out cases which will hopefully aid in making a decision or expose
> > different scenarios.
> >
> > Consider following case for parameter with CAST.
> > select * from customer where CAST(? as char(10)) = name
> > The CAST node will assign the DTD associated with char(10) to the ?. But
> > what should be the collation type for char(10). Currently in the code,
> > it is UCS_BASIC and hence ? ends up getting UCS_BASIC. As a result, the
> > result of the CAST operand gets a collation type of UCS_BASIC amd the
> > comparison against "name" fails with compilation time error. Now doing a
> > CAST on "name" is not an option to fix this problem because CAST(name as
> > char(10)) will result in a character string type with collation of
> > territory based. So, the question is what should be the collation type
> > of char(10) in the eg above?
>
> Why would the two casts be different here? What makes one UCS_BASIC and
> the other territory based?
>
> Dan.
>

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