我只是尝试添加gem'devise',但遇到了一些错误。
但是在此之前,我创建了一个这样的模型用户:
class CreateUsers < ActiveRecord::Migration[5.2]
def change
create_table :users do |t|
t.string :name
t.string :email
t.integer :role
t.string :password_digest
t.timestamps
end
end
end
然后我运行命令“ rails generate devise User”,它创建了一个迁移 add_devise_to_user:
class AddDeviseToUsers < ActiveRecord::Migration[5.2]
def self.up
change_table :users do |t|
## Database authenticatable
t.string :email, null: false, default: ""
t.string :encrypted_password, null: false, default: ""
## Recoverable
t.string :reset_password_token
t.datetime :reset_password_sent_at
## Rememberable
t.datetime :remember_created_at
## Trackable
t.integer :sign_in_count, default: 0, null: false
t.datetime :current_sign_in_at
t.datetime :last_sign_in_at
t.string :current_sign_in_ip
t.string :last_sign_in_ip
## Confirmable
# t.string :confirmation_token
# t.datetime :confirmed_at
# t.datetime :confirmation_sent_at
# t.string :unconfirmed_email # Only if using reconfirmable
## Lockable
# t.integer :failed_attempts, default: 0, null: false # Only if
lock strategy is :failed_attempts
# t.string :unlock_token # Only if unlock strategy is :email
or :both
# t.datetime :locked_at
# Uncomment below if timestamps were not included in your
original model.
t.timestamps null: false
end
# add_index :users, :email, unique: true
add_index :users, :reset_password_token, unique: true
# add_index :users, :confirmation_token, unique: true
# add_index :users, :unlock_token, unique: true
end
def self.down
# By default, we don't want to make any assumption about how to
roll back a migration when your
# model already existed. Please edit below which fields you
would like to remove in this migration.
raise ActiveRecord::IrreversibleMigration
end
end
每当我尝试运行rails db:migrate时,终端就会向我显示这些错误
== 20190331081250 AddDeviseToUsers: migrating =================================
-change_table(:users) 铁轨中止了! StandardError:发生错误,所有以后的迁移都被取消:
Mysql2 :: Error:重复的列名'email':ALTER TABLE users
添加email
varchar(255)DEFAULT''NOT NULL
原因:
ActiveRecord :: StatementInvalid:Mysql2 :: Error:重复的列名'email':ALTER TABLE users
添加email
varchar(255)DEFAULT''NOT NULL
我检查了人们提出的问题和解决方案,但没有一个能帮助我解决这个问题(我是这里的新手)
答案 0 :(得分:0)
阻止change_table
,将列添加到现有表users
中。在change_table
中,您尝试添加列email
,但此列已存在于表users
中。此列是在您的首次迁移中创建的。
您应该在设计迁移中评论以下字符串:
t.string :email, null: false, default: ""
在change_table
(禁止进入)方法之后,在设计迁移中添加跟随字符串:
change_column :users, :email, :string, null: false, default: ""