External employee registration Validation mysql php

Question

I want to register external employees in a mysql database using php.

Each employee has to have in his possession an access credential where it appears: Company, Validity of credential, validity of insurance against risks and medical fitness to work.

I am trying with the following tables: People, Zones, Credentials, Medical Aptitude, Insurance and a record table to calculate how many working hours this employee worked. (In the future I would like to have a log to know the days and hours, but for now so arrives!)

This attached relationship is correct ? Or it can improve ?

Thank you very much.

Answer 1

Your model is functional but you’ve thought about using nvarchar for complex text fields such as the name? varchar saves a string of characters in 8 bits, while nvarchar keeps a Unicode string, allowing accentuation and special characters.

The amount of memory spent with nvarchar is bigger but it is worth spending a few more bytes to not worry more with coding errors.