postgresql Rails 4 迁移：has_and_belongs_to_many 表名
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Rails 4 Migration: has_and_belongs_to_many table name
提问by patrickS
I currently try to switch a rails 3.2 app to rails 4.0. But I have one problem with a has_and_belongs_manymodel.
我目前尝试将 rails 3.2 应用程序切换到 rails 4.0。但是我有一个has_and_belongs_many模型问题。
I have created a test app and I have the same problem there. This is what I have done:
我创建了一个测试应用程序，我在那里遇到了同样的问题。这就是我所做的：
Created two models: foo_clip and foo_url
创建了两个模型：foo_clip 和 foo_url
class FooClip < ActiveRecord::Base
has_and_belongs_to_many :foo_urls
attr_accessible :id, :name
end
class FooUrl < ActiveRecord::Base
has_and_belongs_to_many :foo_clips
attr_accessible :url
end
After this I have updated the migration files:
在此之后，我更新了迁移文件：
class CreateFooClips < ActiveRecord::Migration
def change
create_table :foo_clips do |t|
t.string :name
t.timestamps
end
end
end
class CreateFooUrls < ActiveRecord::Migration
def change
create_table :foo_urls do |t|
t.string :url
t.timestamps
end
end
end
Now I have created the migration file for the has_and_belongs_to_many table
现在我已经为 has_and_belongs_to_many 表创建了迁移文件
class CreateFooClipsFooUrls < ActiveRecord::Migration
def change
create_table :foo_clips_foo_urls do |t|
t.belongs_to :foo_url
t.belongs_to :foo_clip
end
end
end
As last step I created a seed file for testing:
作为最后一步，我创建了一个用于测试的种子文件：
foourl1 = FooUrl.create!(:url => 'http://www.google.com')
foourl2 = FooUrl.create!(:url => 'http://www.apple.com')
fooclip1 = FooClip.create!(:name => 'TestClip1')
fooclip1.foo_urls << foourl1
fooclip1.foo_urls << foourl2
fooclip1.save
Now I did:
现在我做了：
rake db:drop
rake db:create
rake db:migrate
rake db:seed
And got this error:
并得到这个错误：
PG::UndefinedTable: ERROR: relation "foo_clips_urls" does not exist
LINE 5: WHERE a.attrelid = '"foo_clips_urls"'::regcla...
^
: SELECT a.attname, format_type(a.atttypid, a.atttypmod),
pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
FROM pg_attribute a LEFT JOIN pg_attrdef d
ON a.attrelid = d.adrelid AND a.attnum = d.adnum
WHERE a.attrelid = '"foo_clips_urls"'::regclass
AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum
If I take a look at the postgres database the table is called: foo_clips_foo_urls
如果我查看 postgres 数据库，该表被称为：foo_clips_foo_urls
Any ideas why this happens?
任何想法为什么会发生这种情况？
回答by patrickS
I fixed the problem by adding the join_table name to every model like:
我通过将 join_table 名称添加到每个模型来解决这个问题，例如：
has_and_belongs_to_many :foo_urls, :join_table => :foo_clips_foo_urls
