I have some troubles understanding the relation between the a person's First name and Last name in a table. (In a Relational Model)
I've read that the relation is of type: 1-1:
They are linked together.
But the same first name can be attributed to multiple persons. And a single person may have multiple first names…
What I understood is:
Even if "John Doe" has many homonyms around the world, in a database,
his first name would be directly linked to his last name.To avoid this question, we can regroup the last name and first name in
a single row but that would end with humans problems (Formatting
errors: Which order, in capital letters ? separed by spaces or
comas… ?)In the case of a mail generation (for example), I should use the following format:
Title + Last Name (Mr. Doe) instead of (Mr. DOE John).Then I should atomize my two values.
This reflexion should seems useless as my research should be based on ID or others criterias but as I'm still learning, I try to understand the best way possible each details of a databases's conception.
Best Answer
I think the example is a very theoretical one. I have never seen any real world examples of separate
FirstNamesandLastNamestables. Of course you can normalize your database this way, but it wouldn't make much sense in most of the cases.Back to the relation. I think there are two relations here:
I don't think there is a relation between the first and last name.
We can take a slightly different approach with one surname(last name) and multiple "first" names. Then there can be a many to one relationship between first names and person.
However, in most cases first name and last name are just attributes of one person. To solve the issue of mail generation, you can have 3 columns:
first name,middle nameandlast name. Then you use only first and last names for mail generation and store the middle name for other purposes.