在 Rails 中使用带有 Postgres HSTORE 的商店

Question

I have a User Model with a database field 'remark' . I am using Postgres as Database and the 'remark' field is of type HSTORE . So 'remark' stores a hash with extra user information.

As suggested by someone I added a store to my 'User' model like this:

class User < ActiveRecord::Base
  store :remark, accessors: [ :info ]
  #some code
end

Now I can get the value in @user.remark['info'] by using this accessor '@user.info' . That works fine. But when I try to set and save a new value like this:

@user.info = "some info"
@user.save

I get the following error:

ActiveRecord::StatementInvalid: PG::InternalError: ERROR:  Syntax error near '!' at position 4

Is it possible to use a HSTORE type databasefield this way? What am I doing wrong?

Answer 1

Add a custom coder to store :

class User < ActiveRecord::Base
  store :remark, accessors: [ :info ], coder: HstoreCoder
  #some code
end

HstoreCoder class:

class HstoreCoder
  class << self
    def load(hash)
      hash
    end

    def dump(value)
      value.to_hash
    end
  end
end

It should help.

Answer 2

For Rails 5 and hstore use store_accessor instead of store

store_accessor :remark, :info

NOTE: If you are using PostgreSQL specific columns like hstore or json there is no need for the serialization provided by .store. Simply use .store_accessor instead to generate the accessor methods. Be aware that these columns use a string keyed hash and do not allow access using a symbol.

https://api.rubyonrails.org/classes/ActiveRecord/Store.html