Rails - Jan 2009 - ActiveRecord support for find by regular expressions?? Is this possible? / Is there a plugin for this?

Hi,

Is there any way of extending ActiveRecord to do something like:
<model_object>find_by_description_regex(/.*find this.*)   ??

That is ActiveRecord support for find via use of regular expressions?
Perhaps a plugin?  Or is there a reason this doesn''t exist?


-- 
Greg
http://blog.gregnet.org/

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

> Is there any way of extending ActiveRecord to do something like:
> <model_object>find_by_description_regex(/.*find this.*)   ??
>
> That is ActiveRecord support for find via use of regular expressions?
> Perhaps a plugin?  Or is there a reason this doesn''t exist?
Model.find(:all, :conditions => ["column LIKE ?", "%find
this%"])

Would do a simple substring search.  In some databases the above will  
*NOT* find "FIND THIS" because LIKE is case sensitive.  PostgreSQL is
like that.  You can use ILIKE in that case, but don''t know if
that''s
supported elsewhere.

If you aren''t worried about database agnostics you can look to see if  
your particular database support regex conditions...

For example http://www.postgresql.org/docs/8.3/static/functions-matching.html

-philip

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Greg Hauptmann wrote:
> Hi,
> 
> Is there any way of extending ActiveRecord to do something like:  
> <model_object>find_by_description_regex(/.*find this.*)   ??
> 
> That is ActiveRecord support for find via use of regular expressions?  
> Perhaps a plugin?  Or is there a reason this doesn''t exist? 
ActiveRecord''s job is to turn a common Ruby DSL into a big SQL
statement.

Anything that common back-ends can''t do, ActiveRecord can''t
do.

Google [mysql regular expressions] to see if someone has added that to your 
database back-end. Then use find_by_sql (and scrub any tainted data yourself, to
prevent SQL injection attacks like this one: http://xkcd.com/327/ )

Until then, just use LIKE:

   part = ''A''
   Foo.find_all_by_group_id(group_id,
           :conditions => [''name LIKE ?'', part +
''%'' ] )

The % is a wildcard for any length of string - like * in a fileglob match.

-- 
   Phlip


--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

thanks - I''m on mysql so I''m going to try a named_scope like
below (haven''t
run/tested it yet):

  named_scope :regex_matched, lambda { |regex_str|
    { :condition => [" description REGEXP ''?'' " ,
regex_str] }
  }


On Fri, Jan 16, 2009 at 11:37 AM, Phlip
<phlip2005-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> Greg Hauptmann wrote:
> > Hi,
> >
> > Is there any way of extending ActiveRecord to do something like:
> > <model_object>find_by_description_regex(/.*find this.*)   ??
> >
> > That is ActiveRecord support for find via use of regular expressions?
> > Perhaps a plugin?  Or is there a reason this doesn''t exist?
>
> ActiveRecord''s job is to turn a common Ruby DSL into a big SQL
statement.
>
> Anything that common back-ends can''t do, ActiveRecord
can''t do.
>
> Google [mysql regular expressions] to see if someone has added that to your
> database back-end. Then use find_by_sql (and scrub any tainted data
> yourself, to
> prevent SQL injection attacks like this one: http://xkcd.com/327/ )
>
> Until then, just use LIKE:
>
>   part = ''A''
>   Foo.find_all_by_group_id(group_id,
>           :conditions => [''name LIKE ?'', part +
''%'' ] )
>
> The % is a wildcard for any length of string - like * in a fileglob match.
>
> --
>    Phlip
>
>
> >
>

-- 
Greg
http://blog.gregnet.org/

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

One more thing - if your real code is searching for things in
descriptions, you may be
better off with a full-text indexer like Ferret, Sphinx or Solr. At
least in MySQL, a regexp
condition will have to scan every row to find matches, which can get
slow in a hurry.

--Matt Jones


On Jan 15, 8:42 pm, "Greg Hauptmann"
<greg.hauptmann.r...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> thanks - I''m on mysql so I''m going to try a named_scope
like below (haven''t
> run/tested it yet):
>
>   named_scope :regex_matched, lambda { |regex_str|
>     { :condition => [" description REGEXP ''?''
" , regex_str] }
>   }
>
>
>
> On Fri, Jan 16, 2009 at 11:37 AM, Phlip
<phlip2...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> > Greg Hauptmann wrote:
> > > Hi,
>
> > > Is there any way of extending ActiveRecord to do something like:
> > > <model_object>find_by_description_regex(/.*find this.*)  
??
>
> > > That is ActiveRecord support for find via use of regular
expressions?
> > > Perhaps a plugin?  Or is there a reason this doesn''t
exist?
>
> > ActiveRecord''s job is to turn a common Ruby DSL into a big
SQL statement.
>
> > Anything that common back-ends can''t do, ActiveRecord
can''t do.
>
> > Google [mysql regular expressions] to see if someone has added that to
your
> > database back-end. Then use find_by_sql (and scrub any tainted data
> > yourself, to
> > prevent SQL injection attacks like this one:http://xkcd.com/327/)
>
> > Until then, just use LIKE:
>
> >   part = ''A''
> >   Foo.find_all_by_group_id(group_id,
> >           :conditions => [''name LIKE ?'', part +
''%'' ] )
>
> > The % is a wildcard for any length of string - like * in a fileglob
match.
>
> > --
> >    Phlip
>
> --
> Greghttp://blog.gregnet.org/
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---