耙分貝：遷移錯誤：db_development.locations'不存在：SHOW FULL FIELDS FROM`locations`

Question

的database.yml

development: 
    adapter: mysql2 
    encoding: utf8 
    reconnect: false 
    database: db_development 
    username: root 
    password: "123" 
    socket: /var/run/mysqld/mysqld.sock 

# Warning: The database defined as "test" will be erased and 
# re-generated from your development database when you run "rake". 
# Do not set this db to the same as development or production. 
test: 
    adapter: mysql2 
    encoding: utf8 
    reconnect: false 
    database: db_test 
    pool: 5 
    username: root 
    password: "123" 
    socket: /var/run/mysqld/mysqld.sock 

production: 
    adapter: mysql2 
    encoding: utf8 
    reconnect: false 
    database: db_production 
    pool: 5 
    username: root 
    password: "123" 
    socket: /var/run/mysqld/mysqld.sock 

我安裝了寶石mysql2

我在MySQL控制檯創建的數據庫。

後運行耙分貝：從locations

一個遷移從遷移SHOW FULL FIELDS：遷移並顯示錯誤：db_development.locations'不存在

class CreateLocations < ActiveRecord::Migration 
    def self.up 
    create_table :locations do |t| 
     t.string :name 
     t.string :type 
     t.integer :parent_id 
     t.integer :position 

     t.timestamps 
    end 
    end 

    def self.down 
    drop_table :locations 
    end 
end 

什麼錯誤，以及如何解決這個問題？

Answer 1

類型是MySQL中的保護期限https://dev.mysql.com/doc/refman/5.5/en/keywords.html

請更改

t.string :type 

到

t.string :locationType 

，並嘗試遷移

Answer 2

的遷移文件的順序導致這個錯誤。例如讓我們假設我們已經兩種遷移文件那樣：

class CreateDoctors < ActiveRecord::Migration[5.1] 
    def change 
    create_table :doctors do |t| 
     t.string :name 
     t.string :degree 
     t.references :hospital, foreign_key: true 
    end 
    end 
end 

這：

class CreateHospitals < ActiveRecord::Migration[5.1] 
    def change 
    create_table :hospitals do |t| 
     t.string :name 
     t.string :city 
    end 
    end 
end 

所以，我們也有模型文件：

doctor.rb：

class Doctor < ApplicationRecord 
    belongs_to :hospital 
end 

hospital.rb：

class Hospital < ApplicationRecord 
    has_many :doctors 
end 

現在，如果你創建這些模型這樣的順序，一旦doctor和hospital後，當你做你的遷移會問你有一個錯誤。 對於解決方案，您必須先創建模型hospital，然後doctor;因爲doctor的參考列爲hospital。

andolasoft是對的，誰在該問題下發表評論。