RE: Enforced Costraints ??

I had a friend a few years back that started receiving SS checks and he was in his 30's. It turned out that someone that had just retired had the same SSN as he did and was wondering where his checks were.

> -----Original Message-----
> From: dan williams [mailto:danw78704_at_yahoo.com]
> Sent: Tuesday, June 12, 2001 10:31 AM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Enforced Costraints ??
>
>
> Absolutely do not use ssn for a primary key. I ran into that as a
> concern when I created a report. The ssn can be assummed by another
> person, and you would have two persons with the same ssn. Plus the
> already mentioned recycle of the ssn. I know of cases where the ssn
> is taken by a person entering into the US to get work.
>
> --- "Koivu, Lisa" <lisa.koivu_at_efairfield.com> wrote:
> > Well, here's one problem - there is no guarantee that Social
> > Security Number
> > will indeed be unique. SS#'s are reassigned, just like phone
> > numbers are.
> >
> > IMHO, surrogate keys are always a good idea. Has anyone got an
> > example of
> > when a surrogate key is NOT a good idea?
> >
> > > Lisa Koivu
> > > Oracle Database Administrator
> > > 954-935-4117
> > >
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> > >
> > > -----Original Message-----
> > > From: Rao, Maheswara [SMTP:Maheswara.Rao_at_Sungardp3.com]
> > > Sent: Tuesday, June 12, 2001 9:21 AM
> > > To: Multiple recipients of list ORACLE-L
> > > Subject: RE: Enforced Costraints ??
> > >
> > > In a DSS environment, it is a standard practice to create
> > surrogate keys
> > > for
> > > primary key. I never had experience with this (having duplicates
> > in PK).
> > > Perhaps a list member could tell what probs might arise.
> > >
> > > Rao
> > >
> > > -----Original Message-----
> > > Sent: Tuesday, June 12, 2001 6:26 AM
> > > To: Multiple recipients of list ORACLE-L
> > >
> > >
> > > Not good enough ! According to various documents, you should add
> > your own
> > > primary key (surrogate key), which also makes it easier to keep
> > track of
> > > history and combine various sources. I agree with Lee: you should
> > never
> > > implement a PK with non-unique values.
> > >
> > > Remco
> > >
> > > -----Oorspronkelijk bericht-----
> > > Van: Rahul [mailto:rahul_at_ratelindo.co.id]
> > > Verzonden: dinsdag 12 juni 2001 11:56
> > > Aan: Multiple recipients of list ORACLE-L
> > > Onderwerp: RE: Enforced Costraints ??
> > >
> > >
> > > DSS !
> > >
> > >
> > > > ----------
> > > > From: Robertson Lee - lerobe[SMTP:lerobe_at_acxiom.co.uk ]
> > > > Reply To: ORACLE-L_at_fatcity.com
> > > > Sent: Tuesday, June 12, 2001 4:00 PM
> > > > To: Multiple recipients of list ORACLE-L
> > > > Subject: RE: Enforced Costraints ??
> > > >
> > > > am I missing something here ?? Why would you ever need to be in
> > that
> > > > situation (a table with non-unique values in a PK column) ?
> > > >
> > > > Apologies if this is a no-brainer.
> > > >
> > > > Lee
> > > >
> > > >
> > > > -----Original Message-----
> > > > Sent: 12 June 2001 09:41
> > > > To: Multiple recipients of list ORACLE-L
> > > >
> > > >
> > > > i think the solution is to .....
> > > >
> > > > (on a table with non-unique values in a PK candidate column)
> > > >
> > > > 1) create a non-unique index on the pk candidate colunm
> > > > 2) create the pk using enable novalidate clause
> > > >
> > > > this way the existing data will NOT checked for uniqueness, the
> > > constraint
> > > > will be "enforced" for the upcoming data only...
> > > >
> > > > Regards
> > > > Rahul
> > > >
> > > >
> > > > > > ----------
> > > > > > From: Anshumn[SMTP:anshumn.sagar_at_wipro.com]
> > > > > > Sent: Tuesday, June 12, 2001 12:30 PM
> > > > > > To: Rahul
> > > > > > Subject: Re: Enforced Costraints ??
> > > > > >
> > > > > > Hi Rahul,
> > > > > >
> > > > > > That is true. In Oracle 8, there is option to enable the
> > constraint
> > > in
> > > > > > novalidate mode or validate mode. The novalidate mode is
> > the enforce
> > > > > mode,
> > > > > > where only the forthcoming data is checked. It does not
> > check the
> > > > > exisitng
> > > > > > data. The validate mode is the normal constraint enable
> > mode.
> > > > > >
> > > > > > The syntax is
> > > > > > Alter table table enable novalidate constraint name;
> > > > > >
> > > > > > So after I put the constraint in the novalidate mode, the
> > uniqueness
> > > > > will
> > > > > > be checked only amongst the coming data. But if later I set
> > the
> > > > > constraint
> > > > > > ti validate mode(enable), then it may give error as the
> > loaded data
> > > > was
> > > > > > never checked for uniqueness with the exisitng data. In
> > this case I
> > > am
> > > > > > very much confused with the usefulness of this feature.
> > > > > > Can you please give any inputs for the same to clear my
> > doubts ?
> > > > > >
> > > > > > Thanks & Regards,
> > > > > > Anshumn
> > > > > >
> > > > > > Rahul wrote:
> > > > > >
> > > > > > Anshuman,
> > > > > >
> > > > > > whenever u add a constraint to a table, oracle will make
> > > sure all
> > > > > > the data
> > > > > > (if any)
> > > > > > confirms to the constraint added....
> > > > > >
> > > > > > you can enable or disable a constraint (even defer)...
> > dont
> > > confuse
> > > > > > urself
> > > > > > with the term "enforcing a constraint".
> > > > > >
> > > > > > Regards
> > > > > > Rahul
> > > > > >
> > > > > > > ----------
> > > > > > > From: Anshumn[SMTP:anshumn.sagar_at_wipro.com]
> > > > > > > Sent: Tuesday, June 12, 2001 11:26 AM
> > > > > > > To: LazyDBA.com Discussion
> > > > > > > Subject: Enforced Costraints ??
> > > > > > >
> > > > > > > Hi gurus,
> > > > > > >
> > > > > > > Please help me to know the difference between enabling
> > and
> > > > > > enforcing a
> > > > > > > constraint. I need it urgently.
> > > > > > >
> > > > > > > As per my knowledge, enabling a constraint checks for
> > the
> > > > > > > existing data to apply that constraint and then the
> > > constraint is
> > > > > > > applied for the forthcoming data. Whereas enforcing a
> > > constraint
> > > > > > does
> > > > > > > not check the existing records and the constraint is
> > only
> >
> === message truncated ===
>
>
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> Author: dan williams
> INET: danw78704_at_yahoo.com
>
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