如何从投Rails的connection.execute数据类型 [英] How to cast datatype from Rails connection.execute

问题描述

我有，我有太多的痛苦产生AREL查询。供参考（不好意思）：

I've got an AREL query that I generated with much pain. For reference (sorry):

def self.summarize_user(user)
  c   = Arel::Table.new(:categories)
  s   = Arel::Table.new(:skills)
  cp  = Arel::Table.new(:completions)

  query = c.project(c[:id], c[:name], c[:handle])
    .project(s[:id].count.as("total_skills"))
    .project(cp[:id].count.as("total_completed"))
    .project(cp[:verified_on].count.as("total_verified"))
    .join(s).on(s[:category_id].eq c[:id])
    .join(cp, Arel::Nodes::OuterJoin).on(cp[:skill_id].eq s[:id])
    .where(cp[:user_id].eq(user.id).or(cp[:user_id].eq nil))
    .group(c[:id], c[:name], c[:handle])

  # this is the relevant bit
  connection.execute(query.to_sql)
end

这执行，并让我从DB正确的结果是这样的：

This executes and gives me proper results from the DB that look like this:

{ "id" => "13",
  "name" => "Category 16",
  "handle" => "category_16",
  "total_skills" => "4",
  "total_completed" => "0",
  "total_verified" => "0"
}

因此​​，鉴于这种方法已经是一个怪物，我宁愿不通过的结果尝试 .inject 投所有的数字到Fixnum对象。有没有一种方法，在使用 connection.execute ，投领域到正确的数据类型？

So, given that method is already a monster, I'd rather not try to .inject through the results to cast all the numbers into Fixnum. Is there a way, when using connection.execute, to cast fields to their proper datatypes?

推荐答案

您可以利用的的find_by_sql 和 to_json

json_records = Arel::Table.find_by_sql(query.to_sql).to_json

然后你就可以提取您的结果像

Then you can extract your results like

result = JSON.parse json_records

有几种方法可以转换的ActiveRecord 对象散。这只是我个人的preference。

There are several ways to convert ActiveRecord objects to hash. This is just my personal preference.

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