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Re: ORM or JDBC?

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On 11-04-01 11:44 PM, Lawrence D'Oliveiro wrote:
> In message <LQslp.6717$sS4.1488@newsfe11.iad>, Arved Sandstrom wrote:
> 
>> A conceptual model equates to a business model. You might have entities
>> for Person, Address, and LifeEvent, say. There is just enough
>> information in the description of each to support a _business-level_
>> discussion of relationships and identifying information and extra
>> information.
>>
>> It's in the logical model that, assuming we are talking about a
>> relational logical data model, that we might say that Person has
>> person_id as a primary key, that there's a M:N between Person and
>> Address and we describe the join table, there's a 1:N between Person and
>> LifeEvent, we specify exactly what the tables are and what columns
>> exist, what columns are foreign keys, and so forth.
> 
> I still don’t see how you separate between “conceptual” and “logical”. One 
> flows from the other; there is no boundary between them.

There is no super-distinct boundary, no. But there is a boundary
nonetheless. In the conceptual (semantic) model when we are thinking
about Person, we'll have a notion of Person identity - what attributes
of Person make them unique - but at this level that uniqueness could be
opaquely described as PersonID of no particular datatype, and we then go
on to discuss other attributes of Person that are necessary for the
business problem. Similarly, when thinking at this conceptual level
about LifeEvent, we might simply say that each LifeEvent instance will
point at a Person using the PersonId value.

At this stage of the game nobody is talking about tables and rows
(relations and tuples), and if we decide to not use a relational model
we don't have to.

Part of the real-world problem is that in the majority of projects
people already _assume_ relational. So all of their
business/conceptual/semantic work is intertwined with implementation
details.

AHS
-- 
That's not the recollection that I recall...All this information is
certainly in the hands of the auditor and we certainly await his report
to indicate what he deems has occurred.
-- Halifax, Nova Scotia mayor Peter Kelly, who is currently deeply in
the shit

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Re: ORM or JDBC? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-03-31 13:19 +1300
  Re: ORM or JDBC? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-03-31 20:16 -0300
    Re: ORM or JDBC? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-04-01 13:10 +1300
      Re: ORM or JDBC? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-04-01 20:12 -0300
        Re: ORM or JDBC? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-04-02 15:45 +1300
          Re: ORM or JDBC? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-04-02 09:21 -0300
    Re: ORM or JDBC? Tom Anderson <twic@urchin.earth.li> - 2011-04-01 22:38 +0100
      Re: ORM or JDBC? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-04-01 20:03 -0300
        Re: ORM or JDBC? Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-04-02 15:44 +1300
          Re: ORM or JDBC? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-04-02 09:35 -0300
            Re: ORM or JDBC? Lew <noone@lewscanon.com> - 2011-04-02 10:25 -0400

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