This project is archived and is in readonly mode.

The postgres connection adaptor does not correctly identify Primary Keys in Views and Inherited Tables

#6032


 UnitCurrentAttribute.where(UnitCurrentAttribute.arel_table[:id].eq(5))
 NoMethodError: undefined method `eq' for nil:NilClass


ruby-1.9.2-head > UnitCurrentAttribute.arel_table
#<Arel::Table:0xb146080 @name="unit_attributes_closest_now", @engine=ActiveRecord::Base, @columns=nil, @aliases=[], @table_alias=nil, @primary_key=nil, @table_exists=false>

ruby-1.9.2-head > Unit.all.map(&:property)
[
    [0] #<UnitCurrentAttribute:0xb0875cc> {
                    :id => 1,
               :unit_id => "00400002",
               :name_id => "21fc433eab7b0f0298d6e164cbdd2052",
         :short_name_id => "d5d1fe8583fa57c3fe30753f49452321",
        :description_id => "bcaecf06473d29d72fe0a2d03f6cbc3d",
            :valid_from => Wed, 03 Nov 2010,
              :valid_to => Thu, 03 Nov 2011,
            :created_at => Wed, 03 Nov 2010 13:05:19 UTC +00:00,
            :updated_at => Wed, 03 Nov 2010 13:05:19 UTC +00:00
    }
]

Reported by Robert Pankowecki · November 22nd, 2010 @ 01:16 PM

Activity

rails
- State changed from new to open
This issue has been automatically marked as stale because it has not been commented on for at least three months.

The resources of the Rails core team are limited, and so we are asking for your help. If you can still reproduce this error on the 3-0-stable branch or on master, please reply with all of the information you have about it and add "[state:open]" to your comment. This will reopen the ticket for review. Likewise, if you feel that this is a very important feature for Rails to include, please reply with your explanation so we can consider it.

Thank you for all your contributions, and we hope you will understand this step to focus our efforts where they are most helpful.

February 23rd, 2011 @ 12:00 AM
rails
- State changed from open to stale
February 23rd, 2011 @ 12:00 AM

johno

I've had this same problem with updatable views and managed to find out why.

.arel_table returns nil on primary_key (since view has no primary key definition), furthermore table_exists? returns false for views. Here is my workaround.

module UpdatableView
  def arel_table
    @arel_table ||= Arel::UpdatableView.new(table_name, arel_engine)
  end
end

# AREL MEGAHACK
# assume id as primary key
class Arel::UpdatableView < Arel::Table
  def primary_key
    @primary_key ||= self[:id]
  end

  def table_exists?
    true
  end
end

Then use this in your view like this

class MyView < Activerecord::Base
  extend UpdatableView
end

March 9th, 2011 @ 01:34 AM

bingbing
louis vuitton watches

March 26th, 2011 @ 02:02 AM
omarqureshi
This is also a problem if you are using inherited tables. Although in that case, you can get by, through using set_primary_key "id", for views however, it doesn't look like it works so well here.

I'm going to take some time over the weekend in order to get the arel table definition to properly recognize primary keys for views and inherited tables

April 12th, 2011 @ 03:14 PM

omarqureshi

Tag changed from database views, arel, arel2, postgresql to database views, activerecord, arel, arel2, postgresql

Problem method found:

  def primary_key(table)
    row = exec_query(<<-end_sql, 'SCHEMA', [[nil, table]]).rows.first
      SELECT DISTINCT(attr.attname)
      FROM pg_attribute  attr,
           pg_depend     dep,
           pg_namespace  name,
           pg_constraint cons
      WHERE attr.attrelid     = dep.refobjid
        AND attr.attnum       = dep.refobjsubid
        AND attr.attrelid     = cons.conrelid
        AND attr.attnum       = cons.conkey[1]
        AND cons.contype      = 'p'
        AND dep.refobjid      = $1::regclass
    end_sql

    row && row.first
  end

as part of https://github.com/rails/rails/raw/master/activerecord/lib/active_r...

called by Arel by @engine.connection.primary_key(name)

April 17th, 2011 @ 03:53 PM

omarqureshi
- Tag changed from database views, activerecord, arel, arel2, postgresql to database views, activerecord, arel, arel2, postgres-inherited-tables, postgresql
April 17th, 2011 @ 03:55 PM
omarqureshi
- Title changed from Arel 2 does not work well with views on postgresql to The postgres connection adaptor does not correctly identify Primary Keys in Views and Inherited Tables
April 17th, 2011 @ 03:56 PM
omarqureshi
I wonder if instead of the primary key fix being applied here, it should be applied closer to the adaptor - as in something like
```
(row && row.first) || "id"
```
with it yielding way if set_primary_key was used in the class?
April 17th, 2011 @ 04:09 PM