Strange thing with find_by_sql in oracle

Rails
1

I did two sql queries in the same environment and at the same time:
First:
Message.find_by_sql([“select * from messages where id = ?”, 1])
Returns:
gumentError: wrong number of arguments (0 for 1)
from c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/
active_record
ase.rb:1750:in y' from c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/ active_record ase.rb:1750:incompute_type’
from c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/
active_record
ase.rb:1316:in instantiate' from c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/ active_record ase.rb:532:infind_by_sql’
from c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/
active_record
ase.rb:532:in collect!' from c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/ active_record ase.rb:532:infind_by_sql’
from (irb):11
Second:
Message.find_by_sql([“select * from messages where id = ?”, 2])
Returns:
=> []
In table messages, there is a message with id 1, but no message with
id 2
also, I did this query with another table users, all worked well
My environment:
ruby 1.8.6 (2007-09-24 patchlevel 111) [i386-mswin32]
Rails 2.0.2
database: oracle 10
table messages has more columns than table users …
Can anyone help me? Thanks!

2

Ok, i know what happened
i have a column named “Type”
and this makes everything happen
can anyone tells me more details about this ?

3

Thanks!

4

“type” is a preserved keyword in ActiveRecord for implementing “Single
table
inheritance”, so don’t use it as a table column name.

See
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/base.rb:302
:

== Single table inheritance

Active Record allows inheritance by storing the name of the class in

a
column that by default is named “type” (can be changed

by overwriting Base.inheritance_column). This means that an

inheritance looking like this:

class Company < ActiveRecord::Base; end

class Firm < Company; end

class Client < Company; end

class PriorityClient < Client; end

When you do Firm.create(:name => “37signals”), this record will be

saved
in the companies table with type = “Firm”. You can then

fetch this row again using Company.find(:first, "name =

‘37signals’")
and it will return a Firm object.

If you don’t have a type column defined in your table, single-table

inheritance won’t be triggered. In that case, it’ll work just

like normal subclasses with no special magic for differentiating

between
them or reloading the right type with find.

Note, all the attributes for all the cases are kept in the same

table.
Read more:

P of EAA: Single Table Inheritance

Regards,
Jesse

2008/2/18, hei [email protected]:

5

Hi,

U may try this query

Message.find_by_sql(“select * from messages where id = ‘2’”).