Rails - Jun 2006 - Why is rails using DB objects that don''t exist?

I admit it--I''m newb right now.  But only to rails, ruby and friends. 
I''m walking through a "recipe" tutorial but have been stuck
for hours;
it''s time to ask for help.  On Windows I''ve got the latest
ruby, rails,
and webrick; I''ve got the Oracle OCI "thing" to talk to our
Oracle 10g
database, I''ve got Slick Edit and a command line.

I''ve created a recipes table, a sequence to feed its ID primary key 
column, and a trigger that gets fired before record creation.  I can use 
sql at a command line in Oracle''s sqlplus to add records.  No sweat. 
But in the browser I get:

ActiveRecord::StatementInvalid in RecipeController#create

OCIError: ORA-02289: sequence does not exist: select recipes_seq.nextval 
id from dual

I did once have a sequence with that name, but that''s long gone.  In 
fact I''ve dropped and recreated the table, sequence and trigger several
times with new names (except I continue using "recipes" for the table 
name).

I''ve closed and opened and closed firefox.  I''ve restarted
webrick.

I''m having trouble imagining what''s up--because I believe this
little
ruby app isn''t looking into the details of how an incrementing field 
works.  There are clearly remnants somewhere, I just can''t find them.

WTF?!

Thanks anyone for getting me back on track.

-- 
Posted via http://www.ruby-forum.com/.

Although I''m not using oracle, I suspect that rails is using  
standardized names to generate the sql to generate the recipe PK.

..so I''d suggest creating a sequence "recipes_seq" - rails
likely
takes table name + ''_seq'', and runs your quoated sql to obtain
a pk
before doing an insert into recipes.

Jodi

On 24-Jun-06, at 7:24 PM, Frank Burleigh wrote:
> I admit it--I''m newb right now.  But only to rails, ruby and
friends.
> I''m walking through a "recipe" tutorial but have been
stuck for hours;
> it''s time to ask for help.  On Windows I''ve got the
latest ruby,
> rails,
> and webrick; I''ve got the Oracle OCI "thing" to talk to
our Oracle 10g
> database, I''ve got Slick Edit and a command line.
>
> I''ve created a recipes table, a sequence to feed its ID primary
key
> column, and a trigger that gets fired before record creation.  I  
> can use
> sql at a command line in Oracle''s sqlplus to add records.  No
sweat.
> But in the browser I get:
>
> ActiveRecord::StatementInvalid in RecipeController#create
>
> OCIError: ORA-02289: sequence does not exist: select  
> recipes_seq.nextval
> id from dual
>
> I did once have a sequence with that name, but that''s long gone. 
In
> fact I''ve dropped and recreated the table, sequence and trigger  
> several
> times with new names (except I continue using "recipes" for the
table
> name).
>
> I''ve closed and opened and closed firefox.  I''ve
restarted webrick.
>
> I''m having trouble imagining what''s up--because I believe
this little
> ruby app isn''t looking into the details of how an incrementing
field
> works.  There are clearly remnants somewhere, I just can''t find
them.
>
> WTF?!
>
> Thanks anyone for getting me back on track.
>
> -- 
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Jodi Showers wrote:
> Although I''m not using oracle, I suspect that rails is using
> standardized names to generate the sql to generate the recipe PK.
> 
> ..so I''d suggest creating a sequence "recipes_seq" -
rails likely
> takes table name + ''_seq'', and runs your quoated sql to
obtain a pk
> before doing an insert into recipes.
> 
> Jodi
That makes outstanding sense.  I have written pretty much *no* code so 
I''m clueless what the sql looks like.  Is there a means for me to see 
that?  That would make this less magical, but also more comprehensible. 
;-)

And thanks for your reply.

-- 
Posted via http://www.ruby-forum.com/.

Frank Burleigh wrote:
> Jodi Showers wrote:
>> Although I''m not using oracle, I suspect that rails is using
>> standardized names to generate the sql to generate the recipe PK.
>> 
>> ..so I''d suggest creating a sequence "recipes_seq" -
rails likely
>> takes table name + ''_seq'', and runs your quoated sql
to obtain a pk
>> before doing an insert into recipes.
>> 
>> Jodi
> 
> That makes outstanding sense.  I have written pretty much *no* code so 
> I''m clueless what the sql looks like.  Is there a means for me to
see
> that?  That would make this less magical, but also more comprehensible. 
> ;-)
> 
> And thanks for your reply.
http://api.rubyonrails.com/

Rails, by default, guesses at the name of the sequence, as described by 
the previous replier.  To set the name of the sequence

class Recipe< ActiveRecord::Base
  set_sequence_name "recipeseq"   # default would have been
"recipe_seq"
end

Rails uses conventions for a lot of these things, such as table names, 
column names, sequences, etc.  If you name your things like Rails 
expects, you don''t ahve to do anything else.  However, if you
don''t,
that''s not a problem.  You just have to tell rails what they are
called.

For a class Recipe, rails assumes the tables name is loads.  For all 
tables, it assumed the primary key is a column called id.  However, you 
can tell it differently.

Class Recipe < ActiveRecord::Base
  set_table_name "recipe"
  set_primary_key "recipe"
end

If your table was recipe with a primary key called recipe, you can just 
tell it that.  That''s what I do to use ActiveRecord with the database 
for a project at work, where the schema is 10 years old and 
pre-existing.

-- 
Posted via http://www.ruby-forum.com/.

Frank Burleigh wrote:
> Jodi Showers wrote:
>> Although I''m not using oracle, I suspect that rails is using
>> standardized names to generate the sql to generate the recipe PK.
>> 
>> ..so I''d suggest creating a sequence "recipes_seq" -
rails likely
>> takes table name + ''_seq'', and runs your quoated sql
to obtain a pk
>> before doing an insert into recipes.
>> 
>> Jodi
> 
> That makes outstanding sense.  I have written pretty much *no* code so 
> I''m clueless what the sql looks like.  Is there a means for me to
see
> that?  That would make this less magical, but also more comprehensible. 
> ;-)
> 
> And thanks for your reply.
Agile Web Development with Rails is the gold standard for Rails books. 
It''s absolutely outstanding, and in addition to being tremendously 
informative, it''s also fairly interesting to boot.  If you are doing
any
Rails work at all, it''s a non-optional purchase.

http://www.pragmaticprogrammer.com/titles/rails/index.html


-- 
Posted via http://www.ruby-forum.com/.

you can see the sql, as it runs, in the log/development.log. (useful  
for tuning as well)

As noted, the books are really worthwhile. AWD, recipes, etc.

have fun!
Jodi
On 24-Jun-06, at 8:38 PM, Frank Burleigh wrote:
> Jodi Showers wrote:
>> Although I''m not using oracle, I suspect that rails is using
>> standardized names to generate the sql to generate the recipe PK.
>>
>> ..so I''d suggest creating a sequence "recipes_seq" -
rails likely
>> takes table name + ''_seq'', and runs your quoated sql
to obtain a pk
>> before doing an insert into recipes.
>>
>> Jodi
>
> That makes outstanding sense.  I have written pretty much *no* code so
> I''m clueless what the sql looks like.  Is there a means for me to
see
> that?  That would make this less magical, but also more  
> comprehensible.
> ;-)
>
> And thanks for your reply.
>
> -- 
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails