如何使用Rails 5迁移中的级联删除约束创建外键？

Question

我正在使用Rails 5和PostGres 9.5。我想创建从我search_codes表的外键到我的地址表，所以我创造了这个迁移

class CreateSearchCodeTable < ActiveRecord::Migration[5.0] 
    def change 
    create_table :search_codes do |t| 
     t.string :code 
     t.references :address, type: :string, index: true, foreign_key: true, on_delete: :cascade 
     t.index ["code"], name: "index_search_codes_on_code", unique: true, using: :btree 
    end 
    end 
end 

但是什么被创建如下。通知似乎约束的级联部分没有得到创建

myapp=> \d search_codes; 
           Table "public.search_codes" 
    Column |  Type  |       Modifiers 
------------+-------------------+----------------------------------------------------------- 
id   | integer   | not null default nextval('search_codes_id_seq'::regclass) 
code  | character varying | 
address_id | character varying | 
Indexes: 
    "search_codes_pkey" PRIMARY KEY, btree (id) 
    "index_search_codes_on_code" UNIQUE, btree (code) 
    "index_search_codes_on_address_id" btree (address_id) 
Foreign-key constraints: 
    "fk_rails_6bd9792e3b" FOREIGN KEY (address_id) REFERENCES addresses(id) 

如何创建使用Rails的5迁移和Postgres级联的外键约束迁移？

Answer 1

好像是ReferenceDefinition不接受on_delete选项。你可以用add_foreign_key指定删除：

class CreateSearchCodeTable < ActiveRecord::Migration[5.0] 
    def change 
    create_table :search_codes do |t| 
     t.string :code 
     t.references :address, type: :string, index: true 
     t.index ["code"], name: "index_search_codes_on_code", unique: true, using: :btree 
    end 

    add_foreign_key :search_codes, :addresses, on_delete: :cascade 
    end 
end