activerecord

问题 I'm new to rails. Is there an easy way in active record to pass it a hash of data and if the record exists, update it, and if it doesn't, create it? data = {} data["my_id"] = 356345 data["description"] = "test123" w = Descriptions.new(data) Ideally if I ran the above it would only ever have 1 record, not multiple records each time I ran it. 回答1: Assuming you ware wanting the "my_id" bit to be unique you can run Descriptions.find_or_create_by_my_id(data["my_id"]).update_attributes(data) 回答2:

问题 I want to store IP addresses (v4 and v6) in my rails application. I have installed an extension to MySQL adds functions to convert ip strings to binary which will allow me to query by IP range easily. I can use unescaped sql statements for SELECT type queries, thats easy. The hard part is that I also need a way to overwrite the way the field is escaped for insert/update statements. This ActiveRecord statement new_ip = Ip.new new_ip.start = '1.2.3.4' new_ip.save Should generate the following

问题 I'm new in Yii2, and I have a query with right result: SELECT DISTINCT workloadTeam.project_id, wp.project_name, workloadTeam.user_id, workloadTeam.commit_time, wp.workload_type FROM (SELECT p.id, p.project_name, w.user_id, w.commit_time, w.comment, w.workload_type FROM workload as w, project as p WHERE w.user_id = 23 AND p.id = w.project_id) wp INNER JOIN workload as workloadTeam ON wp.id = workloadTeam.project_id But in my ModelSearch.php, I wrote: $user_id = Yii::$app->user->id; $subquery

问题 So I have this model: class Model < ActiveRecord::Base attr_accessible :to_id, :to_type belongs_to :to, polymorphic: true end I was wondering if I could add another relationship when belongs_to is on a specific type: class Model < ActiveRecord::Base attr_accessible :to_id, :to_type belongs_to :to, polymorphic: true belongs_to :to_user, :foreign_key => :to_id, :conditions => ['to_type = ?', 'User'] # doesn't work # OR MAYBE belongs_to :to_user, :foreign_key => :to_id, :foreign_class => 'User'

问题 In Rails 3 ActiveRecord create_table is it possible to include the option :id => false. For example create_table :posts, :id => false do |t| ... end but is it possible to remove the :id column on an existing table in a subsequent up migration? 回答1: You should be able to remove the column just like any other non-id column: remove_column :posts, :id 来源： https://stackoverflow.com/questions/8394253/is-there-a-way-to-remove-the-id-column-in-a-subsequent-rails-3-activerecord-migr

问题 Please see this post as well. Note: The current rake task saves User and Topic objects, but not posts or tags when setting a post object. Question: What is a proper way to describe this relationship in my rake task (shown below) so that it does not throw a can't mass assign attributes exception? Here were my steps: Step 1: Create models class Post < ActiveRecord::Base belongs_to :topic, inverse_of: :posts has_and_belongs_to_many :tags attr_accessible :title, :description, :content, :tags

问题 I'm getting an error (on Sinatra + ActiveRecord Heroku) that Database configuration does not specify adapter . From some research, it looks like this is because Heroku expects there to be no environmental variables used during rackup. I removed the env vars from the db environments file that listed the database URL, but I'm still getting the same error. EDIT: This also worked just a day ago with the db files unchanged, so I'm not sure what could be wrong. 2015-09-01T02:44:40.980448+00:00 app

问题 Consider a User model with the following fields: First name (required) Last name (required) Email (required) Password (required) Phone (required, size: 10 digits) Address (required) And a multi-step signup form with the following steps: 1st step with fields First Name, Last Name, and Email 2nd step with Password, Phone and Address. How would you create a solution to validate the input in each step? The standard ActiveRecord's way doesn't works, since it validates all fields at once. I've

问题 I have a Model which has two attributes (I am showing only two as only those two columns are needed) MyModel place_id ------------------------ user_id 1 ---------------------------------- 1 1 ---------------------------------- 2 1 ---------------------------------- 2 3 ---------------------------------- 3 3 ---------------------------------- 2 3 ---------------------------------- 3 3 ---------------------------------- 1 I want to fetch group by maximum records. Basically I want to fetch for a

问题 I'd like to change the minimum for the id of created objects from 1 to 1000. So when I create in rails my first model object it gets the ID 1000 and not 1. Is there a way to set this in the schema/migration files? 回答1: I am not familiar with MySQL, but for Postgres you can do something like this in your migration file: class CreateCustomers < ActiveRecord::Migration def self.up create_table :customers do |t| t.string :name t.timestamps end execute "SELECT setval('customers_id_seq', 1000);"