Analysis of paradigm graphics and Paradigm

Analysis of paradigm graphics and Paradigm

First, I would like to summarize the problems solved by the five normal patterns that need to be analyzed in one sentence:

1NF: attribute atomicity

2NF: partially dependent

3NF: Pass dependency (key code for non-primary attributes)

BCNF: Pass dependencies (Primary attribute pair candidate keys)

4NF: (the highest level paradigm, which is not often referenced here) D is a set of FD and MVPs established on R, in addition, the left part of X → Y of every non-flat method in D is the Super key of R.

The first paradigm is ignored. The fourth paradigm is not commonly used for drawing omitted.

2NF is as follows:

3NF:

BCNF:

As for 4NF, I am not sure yet. Please advise me. However, in other paradigms, I feel that I can understand myself. If you do not understand me, you can click "Q me" in the upper right corner to discuss it ~

DATABASE function dependency analysis, and 3NF, third paradigm design provides a diagram of function dependencies

Sales personnel table (sales personnel no., sales personnel name)
Customer Info table (customer ID, customer name)
Product Information table (product number, product name, unit price)
Sales table (month, sales personnel number, customer number, product number, sales quantity, cost)

What is the difference between the logical diagram and the physical diagram in the database paradigm?

To put it simply, the logical diagram does not consider storage and distribution. The physical diagram = logical diagram + storage and distribution, typically represented by an object-object model or an erdiagram.