- Depending on the DB you use, you have to have tables for abstract
entities (e.g. in Frontbase you need a table for the root entity,
as PK generation relies on it)
That shouldn't be the case as that (== defining an external name for
the parent entity==) is vertical inheritance. And that soun
On 08/09/2009, at 5:11 PM, Timo Hoepfner wrote:
single table inheritance always worked fine for me. Random things to
watch out for:
- Be careful with NOT NULL constraints. Only make the columns in the
DB NOT NULL, when it must be NOT NULL in the *whole* inheritance
hierarchy (In Chuck and
ad of inheritance, I try to apply the Strategy design pattern.
This usually results in a database table that is similar, if not
identical, in design to a single-table inheritance database table,
ie., it has a "type" field, usually an integer, however the EOModel
has no EOF inheritance
an integer, however the EOModel
has no EOF inheritance artifiacts. The versatility and simplicity of
Strategy design pattern is more desirable and easier to maintain and
extend IMHO ... very easy to add new behaviours. (or in American
English "behavior")
I will try to summariz
Hi,
single table inheritance always worked fine for me. Random things to
watch out for:
- Be careful with NOT NULL constraints. Only make the columns in the
DB NOT NULL, when it must be NOT NULL in the *whole* inheritance
hierarchy (In Chuck and Sacha's most excellent book, there is a
s
We use horizontal in a lot of places - I would avoid vertical. We're
planning on converting horizontal inheritance to single table in
places where the subclasses are very similar for performance reasons.
On Sep 7, 2009, at 4:56 PM, Simon McLean wrote:
Yeah, we use single table all over the
Yeah, we use single table all over the place. works perfectly.
simon
2009/9/7 Travis Britt :
>
> On Sep 6, 2009, at 7:18 PM, Jon Nolan wrote:
>>
>> I now have a project which begs for it. What say you? Do you use
>> inheritance or is my gut feeling correct in telling me to keep on staying
>> aw
On Sep 6, 2009, at 7:45 PM, Jon Nolan wrote:
Travis Britt wrote:
On Sep 6, 2009, at 7:18 PM, Jon Nolan wrote:
I now have a project which begs for it. What say you? Do you use
inheritance or is my gut feeling correct in telling me to keep on
staying away?
Which type? I use single table
Thanks gents. I'm sold.
Lachlan Deck wrote:
On 07/09/2009, at 10:01 AM, Mike Schrag wrote:
i also use single table all the time ... it's easy and predicable.
vertical is just asking for complications. you can make vertical
work, but it's just trickier.
Yep - what he said. Lots of people us
On 07/09/2009, at 10:01 AM, Mike Schrag wrote:
i also use single table all the time ... it's easy and predicable.
vertical is just asking for complications. you can make vertical
work, but it's just trickier.
Yep - what he said. Lots of people use horizontal inheritance too.
(I do use vert
i also use single table all the time ... it's easy and predicable.
vertical is just asking for complications. you can make vertical work,
but it's just trickier.
On Sep 6, 2009, at 7:45 PM, Jon Nolan wrote:
Travis Britt wrote:
On Sep 6, 2009, at 7:18 PM, Jon Nolan wrote:
I now have a proje
Travis Britt wrote:
On Sep 6, 2009, at 7:18 PM, Jon Nolan wrote:
I now have a project which begs for it. What say you? Do you use
inheritance or is my gut feeling correct in telling me to keep on
staying away?
Which type? I use single table inheritance all the time and it works
perfectly.
On Sep 6, 2009, at 7:18 PM, Jon Nolan wrote:
I now have a project which begs for it. What say you? Do you use
inheritance or is my gut feeling correct in telling me to keep on
staying away?
Which type? I use single table inheritance all the time and it works
perfectly. I have no real-wo
I haven't used inheritance in years. My experience was that the hassles you
faced far outweighed the benefits of elegance of design.
I now have a project which begs for it. What say you? Do you use inheritance
or is my gut feeling correct in telling me to keep on staying away?
Thanks,
Jon
_
we do this.
Alan
On May 18, 2007, at 11:43 AM, Chuck Hill wrote:
On May 17, 2007, at 11:21 PM, Lachlan Deck wrote:
Hi there,
first up, can inheritance cross model boundaries? i.e., if I have
ModelA and ModelB both of which have different connection
dictionaries (to different databases
On May 18, 2007, at 2:31 AM, Lachlan Deck wrote:
Okay, I've made some progress, simplified the model, but there's
one final problem that's a bit baffling:
- the foreign key ('clientId') is not being given a value in the sql.
So I have an abstract parent called Taggable with various kids.
Ta
On May 17, 2007, at 11:21 PM, Lachlan Deck wrote:
Hi there,
first up, can inheritance cross model boundaries? i.e., if I have
ModelA and ModelB both of which have different connection
dictionaries (to different databases) can EntityB in ModelB inherit
from EntityA in modelA?
I _think_
Hi there,
On 18/05/2007, at 8:25 PM, Ken Anderson wrote:
Maybe others could chime in more, but one thing I know is that EOF
will use the top entity in the hierarchy to get the primary key so
that all sub-entities have unique keys.
That part I have no problem with. The primary key is being
Lachlan,
Maybe others could chime in more, but one thing I know is that EOF
will use the top entity in the hierarchy to get the primary key so
that all sub-entities have unique keys. This is pretty necessary if
you're going to have a relationship to the super-entity (otherwise,
the forei
Okay, I've made some progress, simplified the model, but there's one
final problem that's a bit baffling:
- the foreign key ('clientId') is not being given a value in the sql.
So I have an abstract parent called Taggable with various kids.
Taggable (Abstract, vertical inheritance)
id
Hi there,
first up, can inheritance cross model boundaries? i.e., if I have
ModelA and ModelB both of which have different connection
dictionaries (to different databases) can EntityB in ModelB inherit
from EntityA in modelA?
If the answer is no then the below is irrelevant - but if yes,
On Jul 2, 2006, at 10:01 AM, Mr. G Brown wrote:Hello,I have a few questions about inheritance, thanks if anybody can help.The parent class would be a Patient, or more accurately, a PatientAlias, because with typos, name changes (marriage or otherwise) information about the same human being could ap
On 03.07.2006, at 4:34 Uhr, Mr. G Brown wrote:
a VerifiedPatient 'is a' PatientAlias , (a special alias, which is
why I asked about inheritance), AND 'has a' to many relationship
with objects of its parent class (PatientAliases). Of course it
will work to have a VerifiedPatient table and
On 03/07/2006, at 12:34 PM, Mr. G Brown wrote:On Jul 2, 2006, at 8:55 PM, Ian Joyner wrote:On 03/07/2006, at 7:27 AM, Mr. G Brown wrote: Yes,A VerifiedPatient would be a subclass of a PatientAlias (from a Java perspective); they would have many properties in common, methods, validations, etc. A Ve
Hi, G. Brown,
Although there are a couple known problems with EO inheritance,
generally, it is fairly reliable. I don't see any problems with using
inheritance here. I'm presuming definitions something like the
following:
PatientAlias
name
address
city
state
zip
te
On Jul 2, 2006, at 8:55 PM, Ian Joyner wrote:On 03/07/2006, at 7:27 AM, Mr. G Brown wrote: Yes,A VerifiedPatient would be a subclass of a PatientAlias (from a Java perspective); they would have many properties in common, methods, validations, etc. A VerifiedPatient would link (from a SQL perspecti
On 03/07/2006, at 7:27 AM, Mr. G Brown wrote:
Yes,
A VerifiedPatient would be a subclass of a PatientAlias (from a
Java perspective); they would have many properties in common,
methods, validations, etc. A VerifiedPatient would link (from a SQL
perspective) to many PatientAliases, and und
Yes,A VerifiedPatient would be a subclass of a PatientAlias (from a Java perspective); they would have many properties in common, methods, validations, etc. A VerifiedPatient would link (from a SQL perspective) to many PatientAliases, and under each PatientAlias there would then be links to inform
Mr G. Brown,I think it would be necessary to understand your object model a little more before being able to recommend if/how to use inheritance. At the moment, I really don't see any entities you have that are good candidates for inheritance, unless I'm misunderstanding your problem. It seems to
Hello,I have a few questions about inheritance, thanks if anybody can help.The parent class would be a Patient, or more accurately, a PatientAlias, because with typos, name changes (marriage or otherwise) information about the same human being could appear, does appear, under several PatientAliases
30 matches
Mail list logo
