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When studying about 3FN I came across 2 interesting examples and I wondered if when making a small change, the examples would continue to meet 3FN.
Explanation about the concept of 3FN
Explaining the Context
Below is an illustration presented by the book to exemplify the normalization of a scheme that meets 3FN. Note the example below and compare with the change.
Book example
Note that as illustrated, an employee can only work in one department and not several, and each department can be composed of several employees.
My Example
I wonder if the attribute Dnumero on the table DF1 key case, the scheme would continue respecting 3FN?
Business rule:
Um funcionário pode trabalhar em mais de um departamento e em cada departamento existe mais de um funcionário.It occurs that this small change of key
Dnumerois required because an employee can work in multiple departments, and each department can be composed of multiple employees.
Note that one of the employees may be the department manager, each department has a manager who is also an employee.
Concluding remarks
How to make the example respect the 3FN and the business rule at the same time?
I don’t think it’s interesting to split a question into two parts, and if you can, put the schematic of how you got your modification
– Rovann Linhalis
The scheme is the same as the book, the only difference is that Dnumero turns primary key along with CPF in the DF1 table, it makes no sense to make another drawing of the same scheme only with this minimal change, but as you asked I will do.
– Jonathas B. C.
I think I get it, you don’t have to draw, if you were using some modeling software, you could just print it, but if it’s going to give you trouble, let it
– Rovann Linhalis
To users who marked the question as pending, someone could guide me somehow, so that the question is removed from the status of [PENDING] the question was well voted, I have already made several edits and continues with this status
– Jonathas B. C.