Rails SQL efficiency for where statement - sql

Question

Is there a more efficient method for doing a Rails SQL statement of the following code?
It will be called across the site to hide certain content or users based on if a user is blocked or not so it needs to be fairly efficient or it will slow everything else down as well.
users.rb file:
def is_blocked_by_or_has_blocked?(user)
status = relationships.where('followed_id = ? AND relationship_status = ?',
user.id, relationship_blocked).first ||
user.relationships.where('followed_id = ? AND relationship_status = ?',
self.id, relationship_blocked).first
return status
end
In that code, relationship_blocked is just an abstraction of an integer to make it easier to read later.
In a view, I am calling this method like this:
- unless current_user.is_blocked_by_or_has_blocked?(user)
- # show the content for unblocked users here
Edit
This is a sample query.. it stops after it finds the first instance (no need to check for a reverse relationship)
Relationship Load (0.2ms) SELECT "relationships".* FROM "relationships" WHERE ("relationships".follower_id = 101) AND (followed_id = 1 AND relationship_status = 2) LIMIT 1

Answer 1

You can change it to only run one query by making it use an IN (x,y,z) statement in the query (this is done by passing an array of ids to :followed_id). Also, by using .count, you bypass Rails instantiating an instance of the model for the resulting relationships, which will keep things faster (less data to pass around in memory):
def is_blocked_by_or_has_blocked?(user)
relationships.where(:followed_id => [user.id, self.id], :relationship_status => relationship_blocked).count > 0
end
Edit - To get it to look both ways;
Relationship.where(:user_id => [user.id, self.id], :followed_id => [user.id, self.id], :relationship_status => relationship_blocked).count > 0