How can I use SQL Server Table Views as Rails Models (Read Only)?

问题

I'm using SQL Server as my database for my Rails project. I'm trying to create some models to use for a 3rd party database and only want to read from this database. So I made a view of the table I wanted to create an object for and then I wanted to point my active record model to it. However, in rails console I don't get back expected results. The only example that gives back some correct information is when I do a count on the object as shown in Example 3 below.

I'm using the following gems to connect to my SQL Server:

gem 'tiny_tds'
gem 'activerecord-sqlserver-adapter'

Also I have installed freetds-dev 0.91-6build1

Example 1

2.2.2 :004 > Game.all
  Game Load (268.7ms)  EXEC sp_executesql N'SELECT [games].* FROM [games]'
 => #<ActiveRecord::Relation [#<Game >, #<Game >, #<Game >, #<Game >, #<Game >, #<Game >, #<Game >, #<Game >, #<Game >, #<Game >, ...]>

Example 2

2.2.2 :001 > Game.first
  SQL (1.1ms)  USE [Incoming]
  Game Load (1.8ms)  EXEC sp_executesql N'SELECT  [games].* FROM [games] OFFSET 0 ROWS FETCH NEXT 1 ROWS ONLY'
TinyTds::Error: Incorrect syntax near '0'.: EXEC sp_executesql N'SELECT  [games].* FROM [games] OFFSET 0 ROWS FETCH NEXT 1 ROWS ONLY'
ActiveRecord::StatementInvalid: TinyTds::Error: Incorrect syntax near '0'.: EXEC sp_executesql N'SELECT  [games].* FROM [games] OFFSET 0 ROWS FETCH NEXT 1 ROWS ONLY'
    from /home/daveomcd/.rvm/gems/ruby-2.2.2/gems/activerecord-sqlserver-adapter-4.2.3/lib/active_record/connection_adapters/sqlserver/database_statements.rb:336:in `each'
    ...
    ...

Example 3

2.2.2 :008 > Game.count
   (4.7ms)  EXEC sp_executesql N'SELECT COUNT(*) FROM [games]'
 => 12541

incoming_model.rb

class IncomingModel < ActiveRecord::Base
  self.abstract_class = true
  self.table_name_prefix = "Incoming.dbo."
  establish_connection "incoming_#{Rails.env}".to_sym
end

game_model.rb

class Game < IncomingModel
  self.table_name = 'games'
end

database.yml

incoming_development:
  <<: *default
  adapter: sqlserver
  host: games-data
  port: 1433
  database: Incoming
  username: ****
  password: ****
  pool: 5
  timeout: 15000

回答1:

So I found that I needed to specify a primary key for the table. So here is the addition I made.

class Game < IncomingModel
  self.table_name = 'games'
  self.primary_key = 'game_id', 'this_other_column'
end

I also had to incorporate for my needs the gem composite_primary_keys, however, that might be more than what some developers will need. Thanks to anyone that took the time to try and help troubleshoot this issue!

来源：https://stackoverflow.com/questions/32118567/how-can-i-use-sql-server-table-views-as-rails-models-read-only

标签

ruby-on-rails

sql-server

freetds

sql-view

tiny-tds