English 中文(简体)
铁路中的布尔字段
原标题:Boolean fields in Rails

在我的铁路应用程序中, 我需要将布林域存储在模型中。 现在, 这造成了一个问题, 因为 Sqlite3 (我用于开发) 使用字符常数 < code> t < /code > 和 f < /code > 来表示真理值。 但是, 我的应用程序将安装到 MySQL 上, 使用字典 < code> true false (分别对应小字 1 和 0) 。 这就使得使用 SQL 条件有问题, 因为表示类型有问题 。

select * from articles where published = true

以铁路表示

Article.where  published = true 

在 Sqlite3 中, 信件 no 将失败, 此列为 True

在铁路中如何更可取地处理布林斯可调适的布林斯?

最佳回答

使用活动记录, 你会做

Article.where(:published => true)

你可能想把这个更进一步, 并把它作为一个范围

class Article < ActiveRecord::Base
  scope :published, where(:published => true)
end

这样在你的控制器里 你就可以离开

@published_articles = Article.published

有关活跃的查询界面的更多信息:http://guides.rubyonrails.org/active_record_querying.html

您还在使用一个任务操作 而不是对等比较

问题回答

暂无回答




相关问题
what is wrong with this mysql code

$db_user="root"; $db_host="localhost"; $db_password="root"; $db_name = "fayer"; $conn = mysqli_connect($db_host,$db_user,$db_password,$db_name) or die ("couldn t connect to server"); // perform query ...

Users asking for denormalized database

I am in the early stages of developing a database-driven system and the largest part of the system revolves around an inheritance type of relationship. There is a parent entity with about 10 columns ...

Easiest way to deal with sample data in Java web apps?

I m writing a Java web app in my free time to learn more about development. I m using the Stripes framework and eventually intend to use hibernate and MySQL For the moment, whilst creating the pages ...

join across databases with nhibernate

I am trying to join two tables that reside in two different databases. Every time, I try to join I get the following error: An association from the table xxx refers to an unmapped class. If the ...

How can I know if such value exists in database? (ADO.NET)

For example, I have a table, and there is a column named Tags . I want to know if value programming exists in this column. How can I do this in ADO.NET? I did this: OleDbCommand cmd = new ...

Convert date to string upon saving a doctrine record

I m trying to migrate one of my PHP projects to Doctrine. I ve never used it before so there are a few things I don t understand. In my current code, I have a class similar to this: class ...