Rails Postgres与自定义外键有很多很多关系

Question

我有一个事实表，clients包含许多业务：

  bus_id, sales,  date  
    1,    $986,  1/1/2016  
    1,    $543,  1/2/2016  
    2,    $921,  1/1/2016  
    2,    $345,  1/2/2016

我想创建一个表opportunities

  bus_id,  opportunity  
     1,     "Upsell"  
     1,    "Upsell More"

如何创建opportunities表格，以便显示每bus_id个商机？

Answer 1

这是迁移命令：

bin/rails g model opportunity custom_foreign_bus_id:integer:index description

<强> businesses.rb

has_many :opportunities, foreign_key: :custom_foreign_bus_id

<强> opportunity.rb

belongs_to :business, foreign_key: :custom_foreign_bus_id

然后获得商机：

Business.find(1).opportunities

或简单地说：

Opportunity.where(custom_foreign_bus_id: 1)

要做多对多，您需要has_and_belongs_to_many关联或加入模式，这是您真正想要的吗？

2.8 Choosing Between has_many :through and has_and_belongs_to_many