The annotate method
is used to add an SQL comment to queries generated from the relation. Here is an example
Bullet.includes(:user).
find_by_id(params[:id])
The above query uses include to eager-load the user table. We can use annotate to add a sql comment to explain the same like
Bullet.includes(:user).
annotate('Eager loading user table').
find_by_id(params[:id])
That's it.
Now when you see the rails server logs, you can find the sql comment which was added in the query explanation.
Processing by BulletsController#show as HTML
Parameters: {"id"=>"5"}
Bullet Load (0.1ms) SELECT "bullets".* FROM "bullets" WHERE
"bullets"."id" = ? /* Eager loading user table */ LIMIT ?
[["id", 5], ["LIMIT", 1]]
↳ app/controllers/bullets_controller.rb:73:in `set_bullet'
User Load (0.1ms) SELECT "users".* FROM "users" WHERE
"users"."id" = ? [["id", 2]]
Caution: Some escaping is performed, however untrusted user input should not be used.
Top comments (0)