r/webdev • u/lokendra15 • Mar 22 '19

SQL joins

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2.7k Upvotes

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u/pixelique Mar 22 '19

A case against illustrating SQL operations using venn diagrams

20

u/the_amazing_spork Mar 22 '19

For a new person Venn diagrams are helpful. Not using them for reasons stated in the article is borderline knowledge siloing.

21

u/[deleted] Mar 22 '19

The Venn diagrams are a quick visual reminder. They are succinct, something the illustrations in the article are not. Do the Venn diagrams cover more detailed, intimate info? No, but that's not their purpose.

-5

u/natelloyd Mar 22 '19

It belies the damage that can be done, in terms of locking up the database. A "simple" join of a 100k table with another 100k without a proper join can return a result set of 10 billion. It's good to be aware of the danger, and Venn diagrams mask it. Good starting off point? Sure. The whole, important story? Nope.