What does First Normal Form mean?
cargocultcode.com
What does First Normal Form mean?
1–10 of 125 posts
Re: What does First Normal Form mean?
#2A clear and concise explanation - well done and rare for the topic.
Re: What does First Normal Form mean?
#3Why does he use the form: "A relation more or less correspond to" and "A relation have"? This doesn't seem to me to be unintended.
Re: What does First Normal Form mean?
#4Why does he use the form: "A relation more or less correspond to" and "A relation have"? This doesn't seem to me to be unintended.
He's somewhat consistent with that. "A relation...correspond", "relation refer to the", "an attribute correspond to".
But diverges on that pattern for "domain": "a domain...corresponds".
Re: What does First Normal Form mean?
#5Why does he use the form: "A relation more or less correspond to" and "A relation have"? This doesn't seem to me to be unintended.
He's somewhat consistent with that. "A relation...correspond", "relation refer to the", "an attribute correspond to". But diverges on that pattern for "domain": "a domain...corresponds".
Level 0 data science: "We have several datapoints."
Level 1 data science: "We have several data."
Level 100 data science: "A relation have a fixed number of attributes (columns) and each column have a domain [...]."
Re: What does First Normal Form mean?
#6I have never understood why RDBs have such general concepts of primary keys, where you can for example let date of birth be a primary key, when in every schema I have ever designed or seen, all rows get unique integer IDs anyway.
Re: What does First Normal Form mean?
#7I have never understood why RDBs have such general concepts of primary keys, where you can for example let date of birth be a primary key, when in every schema I have ever designed or seen, all rows get unique integer IDs anyway.
What about people with the same birthdays?
Re: What does First Normal Form mean?
#8I think he contradicts himself and confuses the data with the information. I don't think delimited values representing a table in a column can be considered normalized.
>Make no mistake, encoding multiple values in a single string is generally a bad design. But it has nothing to do with first normal form. First normal form mean a column should not allow relations as values. A comma-separated string is still just a single string from the perspective of the database type system.
Re: What does First Normal Form mean?
#9Why does he use the form: "A relation more or less correspond to" and "A relation have"? This doesn't seem to me to be unintended.
He's somewhat consistent with that. "A relation...correspond", "relation refer to the", "an attribute correspond to". But diverges on that pattern for "domain": "a domain...corresponds".
may also be english as a second+ language or just a frequent brainfart around pluralization, see the intro:
> This post explains what 1NF actually means and is useful for, and debunk a number of the misunderstandings.
Re: What does First Normal Form mean?
#10I have never understood why RDBs have such general concepts of primary keys, where you can for example let date of birth be a primary key, when in every schema I have ever designed or seen, all rows get unique integer IDs anyway.
What about people with the same birthdays?
Business/requirements/users will often tell you that no two users will have the same birthday/SSN/whatever, but so often that eventually proves incorrect. Just using an auto increment ID as the primary key can prevent a lot of pain down the road.