migrations in rails (sqlite)

hey I have a small problem with my rake

class CreateEvents < ActiveRecord::Migration

  def self.up
    create_table :events do |t|
      t.integer :broadcast_id
      t.integer :position
      t.string :title
      t.string :location
      t.string :link
      t.text :description
      t.datetime :time
  end
    add_foreign_key :events, :broadcast_id, :broadcasts
  end

  def self.down
    remove_foreign_key :events, :broadcast_id, :broadcasts
    drop_table :events
  end

end

problem => add_foreign_key :events, :broadcast_id, :broadcasts

$ rake db:migrate

== CreateEvents: migrating ===================================================
-- create_table(:events)
-> 0.0021s
-- ad开发者_JAVA技巧d_index(:events, :broadcast_id)
-> 0.0004s
rake aborted!
An error has occurred, this and all later migrations canceled:

SQLite3::SQLException: near "FOREIGN": syntax error: ALTER TABLE "events" ADD FOREIGN KEY ("broadcast_id") REFERENCES "broadcasts"(id)

---

Why are you defining foreign keys this way?

If you want a relationship between your Events and Broadcasts then you should look into creating an active record relation. Something like

# Event model
class Event < ActiveRecord::Base
  belongs_to :broadcast
end

# Broadcast model
class Broadcast < ActiveRecord::Base
  has_many :events
end

This way you let rails maintain the foreign key relationship for you. Check out the Rails Guide on active record associations for more info.

---

As of version 3.6.19, SQLite, aka the default development database, supports foreign key constraints, but enforcement of foreign key constraints is turned off by default (for backwards compatibility), to fix it:
Suggested option:

Use another database such as mysql/postgresql as your development database in Rails, and below is an example:

default: &default
adapter: mysql2
encoding: utf8
pool: 5
username: user
password: password
socket: /tmp/mysql.sock

development:
<<: *shared
database: db_development

Other options include:

1. Future versions(4.*) of SQLite has enabled foreign key constraints in default, but as of now, it's not released yet.

2. We could also enable foreign key support by the following command:

   sqlite> PRAGMA foreign_keys = ON;
sqlite> PRAGMA foreign_keys // should print 1

   But please note:

   • it does not persist and you have to do it on every connection;
   • If PRAGMA foreign_keys print nothing, it means your version of SQLite does not support foreign key, please upgrade to 3.6.19 or higher version;
3. Some says we could enable it in connection string, but I didn't find out the correct string in Rails. You could refer to this answer.