Rails迁移：消除约束 [英] Rails Migration: Remove constraint

问题描述

我在Rails应用程序中有一个表（在schema.rb中）如下：

I have a table in a Rails application which (in schema.rb) looks like:

create_table "users", :force => true do |t|
   t.string "name", :null=>false
   t.string "address", :null=>false
end

我想编写一个rails迁移，以允许地址字段为空。即，迁移后，该表如下所示：

I would like to write a rails migration to allow nulls for the address field. i.e. after the migration the table looks like this:

create_table "users", :force => true do |t|
   t.string "name", :null=>false
   t.string "address"
end

我需要怎么做才能消除约束？

What do I need to do to remove the constraint?

推荐答案

不确定可以拨打 t.address 吗？无论如何...我会这样使用 change_column

Not sure you can call t.address? Anyway... I would use change_column like so

change_column :users, :address, :string, :null => true

文档...
http://apidock.com/rails/ActiveRecord/ConnectionAdapters/SchemaStatements/change_column

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