Re: For the SQL Gurus out there, a question

>> We are talking here about Database 101. <<

Good. Since you are clear about the topic we are talking about, all I need to provide some directives for you to either learn or recollect.

ISO/IEC document 2382 International Standard Database Vocabulary details the three levels of discourses for fundamental data representation. i) A conceptual level which captures an information model that can be assimilated by humans.(business model)
ii) A logical level that represents, in an abstract form, some or all of a conceptual model suitable for machine manipulation without regard to actual media or physical devices (logical model) iii) A physical level that maps the logical level to actual storage structures and locations. This involves the actual encodings of data on physical media or devices (the physical model)

Here is Pascal, clearing it up, with examples: http://www.dbdebunk.com/page/page/622537.htm http://www.inconcept.com/JCM/May2003/Pascal.html

Codd's Book RM V2 book, Chapter 29 (Fundamental Laws in Database Management) has descriptions about the three levels of concept -- the user level, logical/semantic level & storage oriented or physical levels. Similar classification of data representation has given by C.J Date in the 2nd Chapter of his Intro to DB book.

During the relational database design endeavor, the external predicate (meaning understood by humans) in the conceptual model is translated to the internal predicate (meaning understood by the DBMS) in the logical model as values in relations. The physical model, which is transparent to the user, encompasses the implementation specific details like the internal data structure, file system, bytes on disk etc & DBMS-specific details like access paths, indexes, clusters etc.

So, instead of making judgements, I suggest you rethink your statement, "All many-to-many relationships must be resolved when moving from a logical design to a physical design." since data representation in a relational database is, by definition, logical & database design using relational approach is by definition, logical design.

>> If you need a course in relational theory and relational database
architecture take it at a local college or university. <<

If this is your general attitude, I suggest you read the following link and get a clue.
http://www.apa.org/journals/psp/psp7761121.html

>> If you are not familiar with the work of E.F. Cobb and Chris Date you
have no business getting behind the keyboard. <<

May I get on with my business?

-- 
- Anith
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