activerecord

问题 [ UPDATED SCHEMA: http://i.imgur.com/fX9CGNh.png ] I'm tasked with developing an appointment booking system that is designed for a small medical office. It is a Rails 3.2 app. I'm having difficulty designing a database schema that makes sense to me. Question: Given the following information, what is the correct relationship between doctors, patients, appointments, chairs and time_slots? Patients need to make appointments with a doctor's office. Depending on the type of appointment, each

问题 [ UPDATED SCHEMA: http://i.imgur.com/fX9CGNh.png ] I'm tasked with developing an appointment booking system that is designed for a small medical office. It is a Rails 3.2 app. I'm having difficulty designing a database schema that makes sense to me. Question: Given the following information, what is the correct relationship between doctors, patients, appointments, chairs and time_slots? Patients need to make appointments with a doctor's office. Depending on the type of appointment, each

问题 Active record is a neet concept but sometimes I find it difficult to get more complicated queries to work. I find this is at least one place the CI docs are lacking. Anyway, This is the sql I wrote. It returns the expected results of quests not yet completed by the user that are unlocked and within the users level requirements: SELECT writing_quests . * FROM `writing_quests` LEFT OUTER JOIN members_quests_completed ON members_quests_completed.quest_id = writing_quests.id LEFT OUTER JOIN

问题 What are the benefits to using an external connection pool? I've heard that most other applications will open up a connection for each unit of work. In Rails, for example, I'd take that to mean that each request could open a new connection. I'm assuming a connection pool would make that possible. The only benefit I can think of is that it allows you to have 1,000 frontend processes without having 1,000 postgres processes running. Are there any other benefits? 回答1: Rails has connection pooling

问题 What are the benefits to using an external connection pool? I've heard that most other applications will open up a connection for each unit of work. In Rails, for example, I'd take that to mean that each request could open a new connection. I'm assuming a connection pool would make that possible. The only benefit I can think of is that it allows you to have 1,000 frontend processes without having 1,000 postgres processes running. Are there any other benefits? 回答1: Rails has connection pooling

问题 I'm trying to make a "generic model" so it can connect to any table of any database. First, I made this class which connects to another database specified (not using the schema) Db class Db < ActiveRecord::Base self.abstract_class = true attr_accessor :error def initialize(item = nil) @error = "" connect super end def connect could_connect = true @error = "" begin ActiveRecord::Base.establish_connection( :adapter => "mysql2", :host => "localhost", :username => "root", :password => "",

问题 I have a legacy database that I'm working on getting ActiveRecord to work with. I've run into a problem with join tables. I have the following: class TvShow < ActiveRecord::Base set_table_name "tvshow" set_primary_key "idShow" end class Episode < ActiveRecord::Base set_table_name "episode" set_primary_key "idEpisode" end And then I have a table called tvshowlinkepisode that has 2 fields: idShow, idEpisode So I have 2 tables and a join between them (so a many to many relationship), however the

问题 I have a legacy database that I'm working on getting ActiveRecord to work with. I've run into a problem with join tables. I have the following: class TvShow < ActiveRecord::Base set_table_name "tvshow" set_primary_key "idShow" end class Episode < ActiveRecord::Base set_table_name "episode" set_primary_key "idEpisode" end And then I have a table called tvshowlinkepisode that has 2 fields: idShow, idEpisode So I have 2 tables and a join between them (so a many to many relationship), however the

问题 I'm trying to save a hash of options in a single DB field. The form is able to save the data to the DB but not able to retrieve it again when I go to edit it (e.g. all the other fields are prepopulated except for the wp_options fields). class Profile < ActiveRecord::Base serialize :wp_options end This is my custom class: class WP_Options attr_accessor :wp_name, :wp_desc, :wp_limit end In my form: <%= form_for(@profile, :remote => true) do |f| %> ... <%= f.fields_for :wp_options do |wp_options

问题 Is there anyway to add a find condition to all Active record models? that is I would like this query ExampleModel.find :all, :conditions=> ["status = ?", "active"] to behave the same way as ExampleModel.find :all in every model Thanks!! 回答1: You could use default_scope: class ExampleModel < ActiveRecord::Base default_scope :conditions => ["status = ?", "active"] end If you want to use this in all your models, you can either subclass ActiveRecord::Base and derive from that in all your models