Rails：您可以将此SQL查询从MySQL转换为SQlite吗？

Question

can you translate this Rails code for MySQL:

def Customer.find_by_key(key)
  Customer.find(:all, :conditions => "pre_name REGEXP '.*#{key}.*' 
      OR sur_name REGEXP '.*#{key}.*' 
      OR street REGEXP '.*#{key}.*' 
      OR zip REGEXP '.*#{key}.*' 
      OR city REGEXP '.*#{key}.*' 
      OR phone_1 REGEXP '.*#{key}.*' 
      OR phone_2 REGEXP '.*#{key}.*' 
      OR email REGEXP '.*#{key}.*' 
      OR company REGEXP '.*#{key}.*'")
end

to SQlite3 code?

Answer 1

Replace these:

pre_name REGEXP '.*#{key}.*'

with LIKE:

pre_name LIKE '%#{key}%'

Or better, use placeholders:

:conditions => [
    "pre_name LIKE :pattern OR sur_name LIKE :pattern ...",
    { :pattern => '%' + key + '%' }
]

SQLite understands REGEXP but it is not implemented by default , you have to implement it yourself. You could add your implementation but there's no point when LIKE will probably do the job.

Answer 2

The REGEXP function isn't defined by default in sqlite3, you'll have to do a bit of work before.

Stick this in an initializer (for example config/initializers/sqlite_regexp.rb ), works with rails 3.1 (see below for rails 3.0):

require 'active_record/connection_adapters/sqlite3_adapter'

class ActiveRecord::ConnectionAdapters::SQLite3Adapter
  def initialize(db, logger, config)
    super
    db.create_function('regexp', 2) do |func, pattern, expression|
      regexp = Regexp.new(pattern.to_s, Regexp::IGNORECASE)

      if expression.to_s.match(regexp)
        func.result = 1
      else
        func.result = 0
      end
    end
  end
end

Code stolen here .

You could of course rewrite your query as in @mu's answer, but I figured it would be nice to know how to really implement the function.

Update

The code above doesn't work for rails 3.0, this should work:

require 'active_record/base'
require 'active_record/connection_adapters/sqlite_adapter'

module ActiveRecord::ConnectionAdapters
  class SQLite3Adapter < SQLiteAdapter
    def initialize(db, logger, config)
      super
      db.create_function('regexp', 2) do |func, pattern, expression|
        regexp = Regexp.new(pattern.to_s, Regexp::IGNORECASE)

        if expression.to_s.match(regexp)
          func.result = 1
        else
          func.result = 0
        end
      end
    end
  end
end