Why is auto_increment "spelled" with an underscore?
I was wondering why `auto_increment` is "spelled" with an underscore, since `primary key` `not null` and such is not?

Is it because `auto_increment` is some old syntactical leftover or such? 
Why is auto_increment "spelled" with an underscore?
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I was wondering why `auto_increment` is "spelled" with an underscore, since `primary key` `not null` and such is not?

Is it because `auto_increment` is some old syntactical leftover or such? 