活动记录 - 获取数据库中的第二个，第三个...项目（无ID） [英] Active Record - Get the second, third.. item in a database (without ID)

问题描述

如何检索数据库中的第二个，第三个..条目。我不想使用由rails生成的自动递增ID。

How to I retrieve the second, third .. entries in a database. I don't want to use the auto incrementing id generated by rails.

由于我从数据库中删除条目，因此ID继续增加。

As I am deleting entries from my database, so the ID continues to increase.

所以我的数据库会有

id : 210 (Even thought it's currently the first value)
id : 211 (Even thought it's currently the second value)

Phone.first将返回第一个如何获取第二个。

I know "Phone.first" will return the first how do I get the second.

子问题

Destroy_all / delete_all -
只删除项目，我可以从数据库中删除所有条目，并使数据库ID从一个开始，而不删除表。

Sub Question-
Destroy_all/delete_all -
only removes the item, Can I remove all entries from the DB and have the DB id's start from one without dropping the table. As I ran into problems.

推荐答案

假设你想要第四个用户：

Say you want the fourth user:

 @users = User.limit(4)
 @fourth_user = @users[3]

关于你的第二个问题， destroy_all 应该做的技巧，因为它触发所有回调。请务必添加：dependent => ：destroy 。

Concerning your second question, destroy_all should do the trick since it triggers all callbacks. Be sure to add :dependent => :destroy in your relationships.

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