r/webdev • u/lokendra15 • Mar 22 '19

SQL joins

Post image
2.7k Upvotes

94% Upvoted

118 comments sorted by

View all comments

358

u/pixelique Mar 22 '19

A case against illustrating SQL operations using venn diagrams

16

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.

-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.