The wisdom of the object mentors (Was: Searching OO Associations with RDBMS Persistence Models)

From: Alfredo Novoa <alfredo_novoa_at_hotmail.com>
Date: 29 May 2006 15:15:08 -0700
Message-ID: <1148940908.338233.159400_at_j73g2000cwa.googlegroups.com>



Robert Martin wrote:

>>> The big problem with OO and RDB is that people try to make them
>>> represent each other. RDB is about data structure an OO is about
>> behavior structure.

>> No no no! RDB is about data management and OO is about application
>> programming.

>That's what I said. This shows profound ignorance of Thesauri.

>> The DBMS must enforce all the business rules (data behavior). The OO
>> applications must enforce the presentation and communication behavior.

>Nahhh. The DBMS must store the data, manage the queries, and enforce
>some integrity rules. Business rules are in the domain of the
>application. We don't want the business rules being done by the
>database. What if we replace the database vendor? Must we rewrite all
>the business rules?

>>> The objects in the OO program should MANIPULATE the
>>> data structures from the RDB.

>> Very wrong. The OO program should TRANSFORM the user input in orders
>> for the DBMS.

>> The OO program is an interface between the users and the DBMS. A
>> friendly substitute for the DBMS console.

>No, a DBMS is a bucket of bits with some low level rules to manage
>those bits. An OO application provides the beavior that the customer
>wants to see. We can completely eliminate the DBMS and replace it with
>another of an entirely different form (non Relational for example) and
>still have all the business behavior we need.

>The people who sell databases have sold you, and the industry, a
>misconception: that the database is the heart of the system. This is
>flawed. The heart of the system is the application code. The database
>is a detail to be decided at the last possible moment and kept in a
>position so flexible that it can be swapped out for another at a whim.

If the mentors are like this, I don't want to imagine the rest.

Regards
  Alfredo Received on Tue May 30 2006 - 00:15:08 CEST

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