Rails join two tables or replace numbers by the words - mysql

Question

I want to write logs to the database and I have often repeated words (syslog, sms, voice, email), I need to instead these words insert numbers (syslog - 1, sms - 2, voice - 3, email - 4), so as not to clog the base repeating words. And then select the words instead numbers
Excuse me, i asked the question wrong. I have data already saved, and i need select it to my index.html.erb. query must be like this: "SELECT triggerid, severity, status, types.name FROM logs, types WHERE logs.type_id = types.id;" logs.type_id = (1, 2, 3, 3, 2, 2, 1), types.name = (email, sms, syslog, voice), types.id = (1, 2, 3, 4,) after query myst be: types.name = (email, sms, syslog, syslog, sms, sms, email). How can i use activerecord fo this result?

Answer 1

I'm not sure what field name/table your wanting to store these numbers in so I'm going to just call it 'FIELD_NAME' and 'TABLE'. Keeping it in mysql you could do this:
Retrieve:
SELECT TABLE.*, case FIELD_NAME WHEN 'syslog' THEN 1 WHEN 'sms' THEN 2 WHEN 'voice' THEN 3 WHEN 'email' THEN 4 ELSE null END as FIELD_ALIAS FROM TABLE
the result will have an attribute of FIELD_NAME with the int value, and an attribute of FIELD_ALIAS with the text version.
Inserting (STR_VALUE is the string version of the field):
INSERT INTO TABLE_NAME (FIELD_NAME) VALUES (case STR_VALUE WHEN 'syslog' THEN 1 WHEN 'sms' THEN 2 WHEN 'voice' THEN 3 WHEN 'email' THEN 4 ELSE null END)
I believe a better alternative though would be to offload this to your model. for simplicity I'm going to refer to your integer version as 'int_value'.
class Address < ActiveRecord::Base
before_save :convert_int_value
def str_value
case self.int_value
WHEN 1 THEN 'syslog'
WHEN 2 THEN 'sms'
WHEN 3 THEN 'voice'
WHEN 4 THEN 'email'
end
protected
def convert_int_value
return nil unless int_value.is_a?(String)
self.int_value = case self.int_value
WHEN 'syslog' THEN 1
WHEN 'sms' THEN 2
WHEN 'voice' THEN 3
WHEN 'email' THEN 4
end
end
Anytime you want the int version, just call int_value on your model. If you want the string call str_value. Additionally you can store the string version, in your int_value and before the record is saved it will convert it for you. This way all you have to pass mysql is an integer.
Update per comment
If your associations are set up correctly (Log belongs_to :type)
Log.includes(:type).each do |l|
l.status
l.type.name #> email, sms, or syslog
end
I realized after the fact there is another solution as well, I think this is more what you were looking for
Log.joins(:type).select('triggerid, severity, status, types.name')
Alt1
Log.joins(:type).select('log.*, types.name')
Alt2
Log.joins('JOINS types ON types.id = logs.type_id').select('log.*, types.name')

Answer 2

are you after one address per client?:
Client.joins(:addresses)
or every address with client info?:
Adress.join(:client)