PLEASE NOTE: Do not publicly post your answers on this Gist, please forward them to your recruiting contact instead ;-)
Each voter can vote in zero or more referenda. Each referendum has one or more questions, and each question is a yes/no vote. Write the simplest normalized schema to describe this in generic SQL statements or as an entity-relationship diagram. Point out where the indexes would be if you want to quickly know the results of a given referendum question, but you never expect to query a single voter's voting record. In what way does the nature of the application affect your design judgment about privacy, and what effect would that have on normalization considerations?
You've getting ready to submit a pull request to the coolapp repo. You branch contains two commits: M, followed by N. The lineage is this:
main: X --> Y --> Z (HEAD commit is Z)
\
your-branch: M --> N (HEAD commit is N)
You want to contribute the code back to the official coolapp repo, but you realize there is a really dumb typo in one of your source code comments (not commit messages) in commit M. You'd still like to submit the pull request as two commits M' and N', where M' is the fixed version of M, and N' is the same exact diff as N. How do you rewrite git history to make this happen? Is N' the same hash as N? Why or why not?
What does the method Module.included do? Provide an example of Module.included being used in Ruby meta-programming and explain exactly how it modifies the affected class(es).
New code was released to the production environment and now the site is SO slow. But it worked great on the single-server staging environment, which has only half the CPU and half the RAM of the production servers!
Here's the code that's behaving poorly:
class Author < ActiveRecord::Base
def books
book_ids = Book.where("author_id = ?", self.id).map { |b| b.id }
book_ids.map { |book_id| Book.find_by_id(book_id) }
end
end
a. What's wrong with this code?
b. Why wasn't the code slow in staging? State the (justifiable) assumptions you are making about the staging environment to support your explanation.
c. What is the much more canonical way to write this code in Rails?
In one Unix command, find all of the files in /tmp whose contents contain the word "foobar" (case-insensitive), and list them all in order from most-recently created to least-recently created.
Usage of the "!important" CSS declaration is often frowned upon by front-end developers. What does the "!important" CSS declaration do? Why do front-end developers suggest using it with caution? What are some cases in which it makes sense to use it?
Take a look at the following:
function *foo(x) {
while (x < 4) {
x += yield x;
}
return x;
}
var bar = foo(3);
console.log( bar.next(1) );
console.log( bar.next(1) );
console.log( bar.next(1) );
What is the output of this code snippet, and why does it behave in the way it does?