Michael Kay wrote:
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it's very easy to do a mapping that supports all the same retrieval queries, but doing a mapping that supports exactly the same set of permitted updates is well nigh impossible.
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One of the issues here is ordering. As soon as you start representing relationships using primary and foreign keys, you lose any natural way of representing order in the relationship
I don’t understand. The following flat data format uses primary/foreign keys to implement nesting:
BookList.dat
Compilers Principles, Techniques, Tools AUT01 Addison-Wesley 1986
Introduction to Compiling Techniques AUT02 McGraw-Hill 1996
Economic Facts and Fallacies AUT03 Basic Books 2011
Economics in One Lesson AUT04 Harper & Brothers 1946
AuthorsList.dat
AUT01 Alfred V. Aho, Ravi Sethi, Jeffrey Ullman
AUT02 J. P. Bennett
AUT03 Thomas Sowell
AUT04 Henry Hazlitt
Suppose I want to update the list of authors. Specifically, I want to add “John Doe” to the beginning of the AUT01 author list:
AUT01 John Doe, Alfred V. Aho, Ravi Sethi, Jeffrey Ullman
That update operation seems pretty straightforward to me. What is the issue that I’m not seeing?
/Roger
