[SOLVED] Wrong SQL for destroy model in Rails 4.2

Wrong SQL for destroy model in Rails 4.2

I have a pretty simlple model:

class SystemKnowledge < ActiveRecord::Base
  validates_presence_of     :system, :value
  validates_numericality_of :value, only_integer: true, greater_than: 0, less_than_or_equal_to: 100

  belongs_to :issue

  attr_accessible :system, :value
end

Once I call model.destroy on an object, I get this error:

ActiveRecord::StatementInvalid: TinyTds::Error: Incorrect syntax near '='.:
EXEC sp_executesql N'DELETE FROM [system_knowledge] WHERE [system_knowledge]. = @0;
SELECT @@ROWCOUNT AS` AffectedRows', N'@0 int', @0 = 275

As far as I get it, the problem is that there is no id field in the generated SQL. What I don't get is why this is happening.

I'm using Rails 4.2 with SQL Express 2014 and TinyTds.

Any help will be greatly appreciated.

Solution

Turns out the problem was there was no primary key set up in the DB table. After adding the primary key explicitly to the table, it all began to work.