索引迁移名称太长

Question

我必须创建一个迁移来进行数据库级别的验证。迁移：

 class DataBaseLevelValidation < ActiveRecord::Migration
  def change
    add_index :benefits_business_changes, [:benefit_id, :business_change_id], :unique => true
  end
end

我遇到的问题是，当我尝试运行 rake db:migration 时出现此错误：

Index name 'index_benefits_business_changes_on_benefit_id_and_business_change_id' on table 'benefits_business_changes' is too long; 
the limit is 62 characters/Users/mariocardoso/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/schema_statements.rb:797:in `add_index_options'

但是如果我将名称更改为更短的版本，我会得到：

SQLite3::SQLException: no such table: main.benefits_businessc: CREATE UNIQUE INDEX "index_benefits_businessc_on_benefit_id_and_business_change_id" ON "benefits_businessc"

我该如何克服这个问题？

我看到的唯一方法是将 'business_change' 模型更改为更短的名称（模型、视图、迁移...所有内容）。

有什么方法可以运行这个迁移而不用长名称引起的错误？

Answer 1

你可以做到

add_index :benefits_business_changes, [:benefit_id, :business_change_id], :unique => true, :name => "a_shorter_name"

一个常见的选择是只使用每列的前几个字母。

索引迁移名称太长

Name of index migration too long

database

ruby-on-rails

rails-migrations

ruby-on-rails-4