Re: Critique of Robert C. Martin's "Agile Principles, Patterns, and Practices"

Isolation creates duplication of concepts and can make it more
difficult to use the existing power and abilities of RDBMS. Most of the
code in your book is WASTED on translating back and forth between two
medium-to-high-level concepts: OO and relational. It is like spending
effort translating between Japanese and Spanish and back rather than
get anything real done.

The payroll system in the book is partitioned into code that knows
about the DB schema, and code that does not. The dividing line is a
set of interfaces that translate high level concepts like "GetEmployee"
into appropriate SQL. To the left of the interfaces the code deals
with Employees. To the right the code deals with SQL, tables, rows,
and columns.

How many getEmployeeBySomeCriteria methods do you think you will end up
with in a normal payroll application? Why do you want to hide predicate
logic and set operations behind a procedural interface?

In any application, OO or not, this translation must take place.

Absolutely not.

There is no duplication. There is no waste.

If you have a table employee and a class employee, you obviously have
duplication. If you have five variants of getEmployeeBySomeCriteria,
you obviously have duplication.

Fredrik Bertilsson
http://mybase.sf.net

.

Relevant Pages

  • Re: Critique of Robert C. Martins "Agile Principles, Patterns, and Practices"
    ... code in your book is WASTED on translating back and forth between two ... To the right the code deals with SQL, tables, rows, ... Martin commits a common OO mistake of making a hierarchy of "employee ...
    (comp.object)
  • Error when using XPBurn
    ... I'm using the XPBurn component, available from MSDN, to manipulate IMAPI from C#. ... Certainly saved the effort of translating the interfaces into .NET. ...
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