postgresql Rails 中的多数据库连接
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Multiple database connection in Rails
提问by Hoang Tran
I'm using active_delegate for multiple connection in Rails. Here I'm using mysql as master_database for some models,and postgresql for some other models.
我在 Rails 中使用 active_delegate 进行多个连接。在这里，我使用 mysql 作为某些模型的 master_database，以及其他模型的 postgresql。
Problem is that when I try to access the mysql models, I'm getting the error below! Stack trace shows that, it is still using the postgresql adapter to access my mysql models!
问题是，当我尝试访问 mysql 模型时，出现以下错误！堆栈跟踪显示，它仍在使用 postgresql 适配器访问我的 mysql 模型！
RuntimeError: ERROR C42P01 Mrelation "categories" does not exist P15 F.\src\backend\parser\parse_relation.c L886 RparserOpenTable: SELECT * FROM "categories"
STACKTRACE
===========
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:507:in `execute'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:985:in `select_raw'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:972:in `select'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in `select_all'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:81:in `cache_sql'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in `select_all'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:661:in `find_by_sql'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:1553:in `find_every'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:615:in `find'
D:/ROR/Aptana/dedomenon/app/models/category.rb:50:in `get_all_with_exclusive_scope'
D:/ROR/Aptana/dedomenon/app/models/category.rb:50:in `get_all_with_exclusive_scope'
D:/ROR/Aptana/dedomenon/app/controllers/categories_controller.rb:48:in `index'
here is my database.ymlfile
这是我的database.yml文件
postgre: &postgre
adapter: postgresql
database: codex
host: localhost
username: postgres
password: root
port: 5432
mysql: &mysql
adapter: mysql
database: project
host: localhost
username: root
password: root
port: 3306
development:
<<: *postgre
test:
<<: *postgre
production:
<<: *postgre
master_database:
<<: *mysql
and my master_databasemodel is like this
我的master_database模型是这样的
class Category < ActiveRecord::Base
delegates_connection_to :master_database, :on => [:create, :save, :destroy]
end
Anyone has any solution??
任何人有任何解决方案？
回答by Hoang Tran
Another way:
其它的办法：
class Abc < ActiveRecord::Base
establish_connection Rails.configuration.database_configuration["test"]
end
回答by Steven Soroka
might want to check out https://github.com/tchandy/octopusnowadays.
回答by Ken
This will change the database connection for a single model object.
这将更改单个模型对象的数据库连接。
$config = YAML.load_file(File.join(File.dirname(__FILE__),
'../config/database.yml'))
class ModelWithDifferentConnection < ActiveRecord::Base
establish_connection $config['connection_name_from_database_yml']
end
If you are using the same server but just a different database file then you can do something like this instead.
如果您使用相同的服务器但只是不同的数据库文件，那么您可以执行类似的操作。
class ModelWithDifferentConnection < ActiveRecord::Base
# Lives in the CURRICULUM database
def self.table_name
"database.table"
end
end
回答by Napoleon
I highly suggest MyReplicationplugin for MySQL adapter which helps you switch the connection at run-time in an elegant way:
我强烈建议MySQL 适配器的MyReplication插件，它可以帮助您在运行时以优雅的方式切换连接：
User.using(:another_database) do
u = User.all
end
回答by karle
I've also had to connect to, and manage, two different databases, so I created a gem called secondbase: http://github.com/karledurante/secondbase
我还必须连接和管理两个不同的数据库，所以我创建了一个名为 secondbase 的 gem：http://github.com/karledurante/secondbase
回答by karle
I tried ur Sample,still getting error!!
我试过你的样品，仍然出错！！
superclass mismatch for class MysqlAdapter
I think ,the problem is with my database.ymlfile .Please check this file
我想，问题出在我的database.yml文件上。请检查这个文件
database_mysql:
adapter: mysql
database: project
host: localhost
username: root
password: root
port: 3306
development:
adapter: postgresql
database: codex
host: localhost
username: postgres
password: root
port: 5432
test:
adapter: postgresql
database: codex
host: localhost
username: postgres
password: root
port: 5432
production:
adapter: postgresql
database: codex
host: localhost
username: postgres
password: root
port: 5432
i start the mongrel in developemnet mode only.
我只在开发网络模式下启动杂种。
here is my model superclass
这是我的模型超类
$config = YAML.load_file(File.join(File.dirname(__FILE__),
'../../config/database.yml'))
class MasterDatabase < ActiveRecord::Base
self.abstract_class = true
establish_connection $config['database_mysql']
end
Please correct me..
请纠正我..
回答by nitecoder
I don't know about active_delegate, but I recently had to access different databases for work applications, and nothing really fit what I wanted. So I wrote something for myself, it's running in production applications as we speak.
我不知道 active_delegate，但我最近不得不访问不同的数据库以用于工作应用程序，但没有什么真正适合我想要的。所以我为自己写了一些东西，正如我们所说，它正在生产应用程序中运行。
Fixed Link connection_ninja
固定链接connection_ninja
