w3d4 notes Flashcards
1
Q
What does the following do?
a, b, c = *Array.new(3, 2)
A
Sets a, b, and c to 2, because a 3 element array of 2s is created with #new, and splat separates out the values.
2
Q
T/F: Never override #initialize in Rails.
A
T
3
Q
What happens when you discard an instance of a model?
A
The db is left untouched, unless you use #destroy
4
Q
Why should you not use instance variables in Rails?
A
They do not persist; the values of them are unreliable.
5
Q
What should you use instead of ::count? Why?
A
You should use #length, b/c ::count will fire the query.
6
Q
What should you use in SQL to check for equivalency to NULL?
A
IS NULL
7
Q
Does SQL have short-circuiting?
A
No
8
Q
How should you structure associations to avoid data duplication?
A
Only connect models in a linear fashion.
