How "perfect" is the database?

Question

I am developing a website to track weight and calorie lifting. I had never developed my own database before, and I decided that I should get as much space as possible before starting coding. Every time I think I am done, it seems to me that it is not perfect. I mainly use MySQL Workbench, but I still have a few questions.

• How important is it to make the database “excellent” in front of you? How hard is it to refactor the database later?
• What does the engine option do? Is all the default tables correct now InnoDB Engine? Any problems with this?
• Are data changes possible after data recording? Maybe not from VARCHAR to INT, but what about VARCHAR (45) - VARCHAR (255)?
• What are the basic database rules that HAVE follow for a successful design?

I also attached an ERM chart. If anyone could point out any obvious violations, that would be greatly appreciated.

Answer 1

Begin as beautifully as you can, and then make it as imperfect as possible.

Answer 2

No practical, operational database is perfect. All warts have.

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Answer 3

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Answer 4

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Answer 5

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Answer 7

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Answer 8

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Answer 9

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Answer 10

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