如何在 Rails 3 中为新列设置值？

发布于 2024-11-07 06:41:32 字数 304 浏览 1 评论 0原文

这可能在另一个问题中，但我找不到它。

我对 Rails 来说是个相对菜鸟。我正在尝试将新列添加到其中已有数据的表中。该列不允许有空值。更新所有现有记录以在这个新列中具有值的最简单方法是什么？我知道它可能在我的迁移的 up 块中，但我不知道语法是什么。

def self.up
  change_table :reminders do |t|
    t.boolean :active
  end
  #model name is Reminder - how to update data with a value?
end

原文

This is probably in another question, but I cannot find it.

I am a relative noobie to Rails. I am trying to add a new column to a table that already has data in it. This column is not going to allow nulls. What is the easiest way to update all the existing records to have a value in this new column? I know it is probably in the up block of my migration, but I don't know what the syntax would be.

def self.up
  change_table :reminders do |t|
    t.boolean :active
  end
  #model name is Reminder - how to update data with a value?
end

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南街九尾狐 2024-11-14 06:41:32

您可以做的是添加列，用所需的值更新表中的所有记录，然后将其更改为不允许空值。

def self.up
  add_column :reminders, :active, :boolean, :default => true
  Reminder.update_all( "active = ?", true )
  change_column :reminders, :active, :boolean, :default => true, :null => :false
end

What you can do is add the column, update all records in the table with the desired value, then change it to not allow nulls.

def self.up
  add_column :reminders, :active, :boolean, :default => true
  Reminder.update_all( "active = ?", true )
  change_column :reminders, :active, :boolean, :default => true, :null => :false
end

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[旋木] 2024-11-14 06:41:32

试试这个：

def self.up
  change_table :reminders do |t|
   t.boolean :active, :default => true #or your value
  end
#model name is Reminder - how to update data with a value?
end

Try this:

def self.up
  change_table :reminders do |t|
   t.boolean :active, :default => true #or your value
  end
#model name is Reminder - how to update data with a value?
end

回复收藏 0 原文

~没有更多了~