I think what we are talking about are surrogate primary keys.
http://en.wikipedia.org/wiki/Surrogate_key
Which is generally accepted as a best practice (well mostly, depending on
the DBA).
regards Malcolm Edgar
On Tue, Feb 3, 2009 at 1:48 AM, Matt Kerr wrote:
> > Do poeple agree w/ me here?
>
The point about saying "no to meaningful pointers" is very clear.
Thank you for your replies and advice. I will perform some tests as soon
as I can and come back with feedback, if I encounter any problems.
Regards,
Nikos
Στις 02-02-2009, ημέρα Δευ, και ώρα 14:21 +0100, ο/η Pierre Lavignotte
έγρ
> Do poeple agree w/ me here?
yes.
On Mon, Feb 2, 2009 at 9:15 AM, Eric Lazarus wrote:
> I can't let this point(er) go buy: JUST SAY NO TO MEANINGFUL POINTERS!
>
> There are BIG problems with having meaningful primary keys in general in
> terms of keeping your program growing and useful long t
I made this mistake once. We spent a LOT of money getting rid of them and in
our case using a meaningful primary key actually stalled our business for
the few months it took to get rid of them.
Don't Do It!
J
On Mon, Feb 2, 2009 at 6:22 AM, Pierre Lavignotte <
pierre.lavigno...@gmail.com> wrote:
But to have the full control on handling the primary keys, I always set the
strategy option, else the keys are handled by cayenne.
2009/2/2 Pierre Lavignotte
> I don't think his question is about sequence usage but about selecting rows
> with specific PK values...
>
> Cordialement,
> Pierre
> Do poeple agree w/ me here?
I do !
All my tables have an autogenerated integer ID. I just need to read it to
point a specific row but I do NOT define it in Cayenne Modeler because
(until now) each time you have to re-engineer you DB schema you lose all the
fields you have manually designed and
Do poeple agree w/ me here?
I agree, but I tend to be pragmatic in such situations. When I have a
choice, I always use generated opaque (meaningless) keys for the
reasons quoted below. When I don't, I map the DB the way it is given
to me.
Andrus
On Feb 2, 2009, at 4:15 PM, Eric Lazarus
I can't let this point(er) go buy: JUST SAY NO TO MEANINGFUL POINTERS!
There are BIG problems with having meaningful primary keys in general in terms
of keeping your program growing and useful long term. When you can avoid it,
avoid it... and when YOU are designing the underlying database from
And to add to that, it is perfectly valid to manually create an
ObjAttribute in the Modeler for plate_num to make it an object
property, even though it's a PK. Cayenne doesn't do it by default, but
the user can still map it if there is a need.
In fact the upcoming 3.0M6 will even have this
I don't think his question is about sequence usage but about selecting rows
with specific PK values...
Cordialement,
Pierre Lavignotte
Ingénieur Conception & Développement
http://pierre.lavignotte.googlepages.com
On Mon, Feb 2, 2009 at 2:25 PM, Alessio Giovanni Baroni <
alessiogiovanni.bar...@gm
It's all ok. But, you are sure that in Entity screen, you are selected
"Custom Sequence" on the "PK Generation Strategy"?
If you do it, AND you add a filed relative to a pk column, you can handling
the keys, without the cayenne's control.
Hi.
2009/2/2 Νίκος Παράσχου
> First of all thank you fo
Here is what I use when I want to get Recomaster entity with primary key =
id :
Recomaster recomaster = (Recomaster)
DataObjectUtils.objectForPK(context, Recomaster.class, id);
And in the Recomaster class, I also have a method that gives me the primary
key :
public Integer getId() {
First of all thank you for your replies.
I have the following table:
Vehicle (
plate_num CHAR(10) NOT NULL,
mixed_weight DOUBLE PRECISION NOT NULL,
type CHAR(30) NOT NULL,
manufacturer CHAR(20),
PRIMARY KEY (plate_num)
)
In Cayenne Modeller I have the dbEntity
When you create the mapping table->object, you must to specify "PK
Generation Strategy" as "Custom Sequence", and you have
control complete on keys handling. Next, in the attributes of the table and
the relative object, you must to add the field for the primary
key, selecting the field PK also.
Al
Hi Nikos,
If you need PK for all your tables, then maybe you need to generate them.
But if you only need to use them for a couple tables then you should look at
DataObjectUtils class.
Cheers,
Pierre
Cordialement,
Pierre Lavignotte
Ingénieur Conception & Développement
http://pierre.lavignotte.go
Hello,
It is the first time I am using cayenne and I have some questions
regarding the primary keys.
What I want to do is select some rows of a table where the PK has a
specific value. The problem is I can't access the PK. I can specify
qualifiers only with the non-PK columns. The PKs I am using
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