Rails查询执行2个查询

Question

I have a simple rails query like

a = A.where(type: 'user')
if a.count > 1
  #Log Information
end
return a

Rails does lazy loading where it doesn't query the database unless some operation on the result set is executed. This is a fine behavior. But in my case rails ends up executing 2 queries because I call a.count before operating on a

SELECT COUNT(*) FROM `a` WHERE `a`.`type` = 'user';
SELECT  `a`.* FROM `a` WHERE `a`.`type` = 'user';

Is there any way I can ask rails to perform the query immediately so that only the second query is executed and the count is returned from the dataset.

Answer 1

You can force the results into an array. I think that to_a will work for that, but entries is a clearer way express that intention since its job is to iterate over the items in an Enumerable and return an array of the enumerated results.

a = A.where(type: 'user').entries
if a.count > 1
  #Log Information
end
return a