|2003年 1月16日||WRAP-UP: THE RULES||BACK >> 目次|
The procedure for preparing T-ERD:
□ a ≠ b
A "combination-table", taisyou-hyo, shall be created, and
The identifier of the resource shall be posted into the event.
If "one-to-one" or "one-to-many",
If "many-to-one" or "many-to-many",
□ a = b (recursive)
A "recursive" table, "entity. entity. as recurring", shall be created for the "recursive" structure and decomposed into a binary format of "a parent-child" combination.
Now you can prepare T-ERD! It's easy, isn't it?
Well, the T-ERD you've now prepared, how can you prove if it's right (sound and correct)?
If you cannot prove that it's correct, it may be just an arbitrary work--many system engineers can prepare many diagrams with the same data, and all of the diagrams might be dissimilar.....they cannot be called the products produced through engineering techniques.
Next time, I'll take a technique, "connotation and extension", to prove that the data clusters you've created should be right.
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