[PATCH] Fixed non-standard SQL generated by preloading has_and_belongs_to_many associations
Reported by Antonio Cangiano | June 11th, 2008 @ 08:42 PM | in 2.1.1
Preloading has_and_belongs_to_many associations generates non-standard SQL which breaks standard-compliant databases like DB2 and Oracle.
Example:
class Project < ActiveRecord::Base
has_and_belongs_to_many :developers
end
class Developer < ActiveRecord::Base
has_and_belongs_to_many :projects
end
p Project.find(:all, :include => :developers)
The previous code generates queries along the lines of:
SELECT developers.*, t0.project_id as _parent_record_id FROM developers INNER JOIN developers_projects as t0 ON developers.id = t0.developer_id WHERE (t0.project_id IN (1,2))
An SQL identifier cannot begin with an underscore, and this is true for all three versions of the standard (92, 99 and 2003). You can verify the non-conformity of the generated SQL through this validator: http://developer.mimer.com/valid...
In the attached patch, I renamed _parent_record_id with the_parent_record_id.
Please note that no further tests are required given that the test cases in cases/associations_test.rb already cover this specific issue.
Comments and changes to this ticket
-
Jeremy Kemper June 12th, 2008 @ 01:28 AM
- → Milestone changed from “” to “2.1.1”
- → State changed from “new” to “open”
- → Assigned user changed from “” to “Jeremy Kemper”
-
Repository June 12th, 2008 @ 01:36 AM
- → State changed from “open” to “resolved”
(from [4689496b525526a776004c4986d98b0ce62309d5]) Fixed non-standard SQL generated by preloading has_and_belongs_to_many association. [#394 state:resolved]
-
Don McClean July 27th, 2008 @ 12:30 AM
- → Tag changed from “” to “activerecord bug has_and_belongs_to_many patch standard-sql”
I manually patched my source with your fix and still got an
error. I am running Oracle 9.2. The second portion of the
above example 'as t0' was still causing an error. Removing the
'as' fixed the problem.
Regards,
Don McClean
-
Antonio Cangiano July 28th, 2008 @ 01:18 AM
Don, this must be an Oracle peculiarity. Using the "as t0" is standard SQL. It's OK to omit it though, if it helps Oracle, because omitting it respects the standard too
-
Don McClean July 30th, 2008 @ 03:05 PM
Antonio,
Since removing the 'as' still would be standard SQL, it
would be appreciated if you could remove it.
Thanks and Regards,
Don McClean
-
Brent Miller November 20th, 2008 @ 05:02 PM
Since this ticket seems to be closed, the "as" issue is being addressed in ticket #1405
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