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boredemployee·

I always thought venn diagram was a good representation but I think I was wrong.

Edit: Why did I get down voted? :)

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I would also like to know why you are getting downvoted.

Even wikipedia uses a Venn diagram to explain JOIN https://en.wikipedia.org/wiki/Join_(SQL) .

Not trying to use an argument from authority but just pointing out that this is not unheard of.

Venn diagrams are a terrible way to describe join types (and, tbh, I don’t understand why Wikipedia has these) because it makes it look like applying an 1:1 relationship. In a M:N relationship „artefacts“ (for lack of better words) of both tables would appear multiple times, and the venn diagram obscures this fact

> because it makes it look like applying an 1:1 relationship.

People can form different mental models of the same abstraction so I see what you are saying

I've never seen it that way because "Venn diagrams do not generally contain information on the relative or absolute sizes (cardinality) of sets." (see https://en.wikipedia.org/wiki/Venn_diagram).

I've always found Coding Horror's Venn diagram depiction of SQL joins quite enlightening:

https://blog.codinghorror.com/a-visual-explanation-of-sql-jo...

Because a venn diagram does not describe join mechanics well. A venn diagram does however describes the UNION, INTERSECT, EXCEPT part of sql.

https://blog.jooq.org/say-no-to-venn-diagrams-when-explainin...

And more meta, it is an innocent slightly incorrect statement, stuff like that should not be down voted, reply with a correction. Save down votes for outright malicious posts.

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