CODEWITHSUNDEEP
mysqlruby-on-railsregexruby-on-rails-3activerecord
Misha Moroshko
Misha Moroshko

Reputation: 171321

How to specify Ruby regex when using Active Record in Rails?

To get all jobs which invoice_number is a pure number I do:

Job.where("invoice_number REGEXP '^[[:digit:]]+$'")

Is it possible to do the same by specifying the regex in Ruby rather than MySQL ?

Upvotes: 13

Views: 8566

Answers (3)

Gurudath BN
Gurudath BN

Reputation: 1411

we can write like

scope :only_valid_email_record , :conditions=>["email_id ~ ?","^([a-zA-Z0-9_.'-])+@(([a-zA0-9-])+.)+([a-zA-Z0-9]{2,4})+$"]

It works fine in rails 3.

Upvotes: 1

Mark Thomas
Mark Thomas

Reputation: 37517

One way is

Job.all.select{|j| j =~ /^\d+$/}

but it will not be as efficient as the MySQL version.

Another possibility is to use a named scope to hide the ugly SQL:

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

Then you have Job.all_digits.

Note that in the second example, you are assembling a query for the database, so regex_str needs to be a MySQL regex string instead of a Ruby Regex object, which has a slightly different syntax.

Upvotes: 13

John Bachir
John Bachir

Reputation: 22721

Your best bet is either Regexp#tos or Regexp#source or Regexp#inspect.

But I can't think of why you would want to do this -- Ruby doesn't make it easy to compose Regexps programmatically (which is the only reason I can think of why one might want to compose at one level and submit it to another).

Upvotes: 2

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