trafodion-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Eric Owhadi <eric.owh...@esgyn.com>
Subject RE: [DISCUSS] Change the default setting of ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON
Date Tue, 02 Feb 2016 22:09:24 GMT
Can you elaborate on this?
As I understand Suresh message, even with NULLABLE columns, we still assume
uniqueness of the concatenation of all column making up the PK.
So your sentence "a full PK will map to up to one row" is still respected?
Or am I misunderstanding?
Eric

-----Original Message-----
From: Qifan Chen [mailto:qifan.chen@esgyn.com]
Sent: Tuesday, February 2, 2016 4:05 PM
To: dev <dev@trafodion.incubator.apache.org>
Subject: Re: [DISCUSS] Change the default setting of
ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON

Allowing NULL in primary key columns could break some existing assumptions
in our code base on PKs. For example, a full PK will map to up to one row,
which is a logic constraint that the compiler takes full advantage of.

Thanks --Qifan

On Tue, Feb 2, 2016 at 4:01 PM, Dave Birdsall <dave.birdsall@esgyn.com>
wrote:

> ANSI in general does not concern itself with physical issues. So no
> partitioning, no indexing, and so on in ANSI.
>
>
> -----Original Message-----
> From: Eric Owhadi [mailto:eric.owhadi@esgyn.com]
> Sent: Tuesday, February 2, 2016 1:59 PM
> To: dev@trafodion.incubator.apache.org
> Subject: RE: [DISCUSS] Change the default setting of
> ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON
>
> Great, so my 2 cts is that we should not worry about ANSI on the
> default not supporting NULL, since ANSI did not account for
> partitioning...
> Eric
>
> -----Original Message-----
> From: Roberta Marton [mailto:roberta.marton@esgyn.com]
> Sent: Tuesday, February 2, 2016 3:55 PM
> To: dev@trafodion.incubator.apache.org
> Subject: RE: [DISCUSS] Change the default setting of
> ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON
>
> Store by is not ANSI standard.
>
>    Roberta
>
> -----Original Message-----
> From: Eric Owhadi [mailto:eric.owhadi@esgyn.com]
> Sent: Tuesday, February 2, 2016 1:53 PM
> To: dev@trafodion.incubator.apache.org
> Subject: RE: [DISCUSS] Change the default setting of
> ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON
>
> Do you happen to know if STORE BY is part of the ANSI standard, and if
> ANSI mandate that anything in STORE BY must be part of the PK?
> Eric
>
> -----Original Message-----
> From: Dave Birdsall [mailto:dave.birdsall@esgyn.com]
> Sent: Tuesday, February 2, 2016 3:45 PM
> To: dev@trafodion.incubator.apache.org
> Subject: RE: [DISCUSS] Change the default setting of
> ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON
>
> Our default behavior would not be ANSI standard if this is changed. I
> don’t know if that is a compelling reason not to do this though.
>
> Dave
>
> -----Original Message-----
> From: Suresh Subbiah [mailto:suresh.subbiah60@gmail.com]
> Sent: Tuesday, February 2, 2016 1:37 PM
> To: dev@trafodion.incubator.apache.org
> Subject: [DISCUSS] Change the default setting of
> ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON
>
> Hi,
>
> Do you foresee potential problems if  we change the default setting
> for ALLOW_NULLABLE_UNIQUE_KEY_CONSTRAINT to ON. ?
> It does seem that users are asking for using and setting this CQD in
> their individual applications.
> Other than JIRA 1801, there are no known issues when this attribute is
> set to ON.
> Having the default set to ON could make Trafodion easier to use.
>
> I can file a JIRA if there is agreement or if we think the discussion
> should be moved to a JIRA.
>
> Thank you
> Suresh
>



--
Regards, --Qifan

Mime
View raw message