Tutorial by Examples: ti

A has_and_belongs_to_many association creates a direct many-to-many connection with another model, with no intervening model. For example, if your application includes assemblies and parts, with each assembly having many parts and each part appearing in many assemblies, you could declare the models...

We can check the status of migrations by running 3.05.0 rake db:migrate:status 5.0 rails db:migrate:status The output will look like this: Status Migration ID Migration Name -------------------------------------------------- up 20140711185212 Create documentation pages up ...

In order to compile and run SystemVerilog code a tool called a simulator is needed. Most commonly, commercial tools from one of the Big Three EDA companies is used: Cadence Incisive Mentor Graphics QuestaSim Synopsys VCS Other EDA vendors also provide simulators: Aldec Riviera-PRO Xilinx...

Cloning an object by implementing the Cloneable interface. public class Sheep implements Cloneable { private String name; private int weight; public Sheep(String name, int weight) { this.name = name; this.weight = weight; } @Override public Ob...

If you want to create multiple uploads, first thing you might want to do is create new model and set up relations Let's say you want an multiple images for the Product model. Create an new model and make it belongs_to your parent model rails g model ProductPhoto #product.rb has_many :product_p...

To generate a new mailer, enter the following command rails generate mailer PostMailer This will generate a blank template file in app/mailers/post_mailer.rb named PostMailer class PostMailer < ApplicationMailer end Two layout files will also be generated for the email view, one for the...

Rails provides a lot of generators, for controllers too of course. You can generate a new controller by running this command in your app folder rails generate controller NAME [action action] [options] Note: You can also use rails g alias to invoke rails generate For example, to generate a cont...

You can rescue a RecordNotFound exception with a redirect instead of showing an error page: class ApplicationController < ActionController::Base # your other stuff rescue_from ActiveRecord::RecordNotFound do |exception| redirect_to root_path, 404, alert: I18n.t("errors.record...

Database configuration of a rails project lies in a file config/database.yml. If you create a project using rails new command and don't specify a database engine to be used then rails uses sqlite as the default database. A typical database.yml file with default configuration will look similar to fol...

Testing your Active Record models through your command line interface is simple. Navigate to the app directory in your terminal and type in rails console to start the Rails console. From here, you can run active record methods on your database. For example, if you had a database schema with a User...

console.count([obj]) places a counter on the object's value provided as argument. Each time this method is invoked, the counter is increased (with the exception of the empty string ''). A label together with a number is displayed in the debugging console according to the following format: [label]: ...

Debug.log's second argument is always returned, so you could write code like the following and it would just work: update : Msg -> Model -> (Model, Cmd Msg) update msg model = case Debug.log "The Message" msg of Something -> ... Replacing case msg o...

There are a few libraries for unit testing in Common Lisp FiveAM Prove, with a few unique features like extensive test reporters, colored output, report of test duration and asdf integration. Lisp-Unit2, similar to JUnit Fiasco, focusing on providing a good testing experience from the REPL. Su...

If, instead of always having a content script injected based on the URL, you want to directly control when a content script is injected, you can use Programmatic Injection. Minimal example JavaScript chrome.tabs.executeScript({file: "content.js"}); CSS chrome.tabs.insert...

Same conditions, multiple scripts If you need to inject multiple files with all other conditions being the same, for example to include a library, you can list all of them in the "js" array: "content_scripts" : [ { "js": ["library.js", "conten...

As Go uses implicit interface implementation, you will not get a compile-time error if your struct does not implement an interface you had intended to implement. You can test the implementation explicitly using type casting: type MyInterface interface { Thing() } type MyImplementer struct {} ...

First action to take is to create a new project File > New > Project. Here Single View Application is selected, but you can choose the one that fits your project the best. The next step in setup of core data is adding the information to your project. The important part in the photo below is...

First it is important to understand that the Core Data Model is the *.xcdatamodeld file. You will notice you have not entities. You will have to create one yourself. At the bottom of Xcode you will notice a button that says "Add Entity" click it and you will have a new entity in the ...

Under the attributes section you add the attributes to your model. This button is a plus located at the bottom of the section. You can add any attributes that are relevant to your app. You have several options of types to choose from ranging from Booleans to Dates and more. The Inspector panel also ...

Relationships are relationship between entities that can be one-to-one or one-to-many. Creating a relationship is not needed to use Core Data.