Tutorial by Examples: reat

CREATE TABLE table_name ( id INT NOT NULL AUTO_INCREMENT, json_col JSON, PRIMARY KEY(id) );

Giving your list a type To create a list you need a type (any class, e.g. String). This is the type of your List. The List will only store objects of the specified type. For example: List<String> strings; Can store "string1", "hello world!", "goodbye", etc, b...

If you have a vector in polar form (direction & distance) you will want to convert it to a cartesian vector with a x and y component. For referance the screen coordinate system has directions as 0 deg points from left to right, 90 (PI/2) point down the screen, and so on in a clock wise direction...

Sometimes we want to design our own UI for "Sign In With Facebook" button instead of the original button that comes with FacebookSDK. In your storyboard, drag your UIButton and set it however you want it to be. Ctrl + drag your button to your view controller as IBAction. Inside the IB...

To create a new Rails 5 API, open a terminal and run the following command: rails new app_name --api The following file structure will be created: create create README.rdoc create Rakefile create config.ru create .gitignore create Gemfile create app create app/as...

The macro WITH-INPUT-FROM-STRING can be used to make a stream from a string. (with-input-from-string (str "Foobar") (loop for i from 0 for char = (read-char str nil nil) while char do (format t "~d: ~a~%" i char))) ; 0: F ; 1: o ; 2: o ; 3: b ;...

Swift let color = UIColor.redColor() let size = CGSize(width: 200, height: 200) UIGraphicsBeginImageContextWithOptions(size, false, 0.0) CGContextSetFillColorWithColor(UIGraphicsGetCurrentContext(), color.CGColor) CGContextFillRect(UIGraphicsGetCurrentContext(), CGRect(origin: .zero, size: si...

Creating a custom ImplicitNamingStrategy allows you to tweak how Hibernate will assign names to non-explicitly named Entity attributes, including Foreign Keys, Unique Keys, Identifier Columns, Basic Columns, and more. For example, by default, Hibernate will generate Foreign Keys which are hashed an...

Split Function returns a zero-based, one dimensional array containing a specified number of substrings. Syntax Split(expression [, delimiter [, limit [, compare]]]) PartDescriptionexpressionRequired. String expression containing substrings and delimiters. If expression is a zero-length string(&q...

Create a model (lets call it User) by running: $ rails g model User which will generate the file app/models/user.rb: class User include Mongoid::Document end This is all you need to have a model (albeit nothing but an id field). Unlike ActiveRecord, there is no migration files. All the...

MySQL does not provide a built-in way to create pivot queries. However, these can be created using prepared statements. Assume the table tbl_values: IdNameGroupValue1PeteA102PeteB203JohnA10 Request: Create a query that shows the sum of Value for each Name; the Group must be column header and Name...

Creating backpressured data sources is the relatively easier task when dealing with backpressure in general because the library already offers static methods on Observable that handle backpressure for the developer. We can distinguish two kinds of factory methods: cold "generators" that ei...

Basic HTTP calls don't provide code-reusability, however. And they can get confused with all the other features you're trying to implement. For those reasons, it's common to implement an API wrapper. Foo = { identify: function(input){ return Http.get('http://foo.net/api/identify/' + input...

After creating an API wrapper, it's likely that you may want to create an Atmosphere package to redistribute it and share it between applications. The files of your package will probably look something like this. packages/foo-api-wrapper/package.js packages/foo-api-wrapper/readme.md packages/foo-...

Custom events usually need custom event arguments containing information about the event. For example MouseEventArgs which is used by mouse events like MouseDown or MouseUp events, contains information about Location or Buttons which used to generate the event. When creating new events, to create a...

A cancelable event can be raised by a class when it is about to perform an action that can be canceled, such as the FormClosing event of a Form. To create such event: Create a new event arg deriving from CancelEventArgs and add additional properties for event data. Create an event using EventH...

PostgreSQL and SQLite To create a temporary table local to the session: CREATE TEMP TABLE MyTable(...); SQL Server To create a temporary table local to the session: CREATE TABLE #TempPhysical(...); To create a temporary table visible to everyone: CREATE TABLE ##TempPhysicalVisibleToEveryo...

Named vector can be created in several ways. With c: xc <- c('a' = 5, 'b' = 6, 'c' = 7, 'd' = 8) which results in: > xc a b c d 5 6 7 8 with list: xl <- list('a' = 5, 'b' = 6, 'c' = 7, 'd' = 8) which results in: > xl $a [1] 5 $b [1] 6 $c [1] 7 $d [1] 8 Wi...

This example assumes that you have experience in creating Rails applications. To create an API-only app in Rails 5, run rails new name-of-app --api Add active_model_serializers in Gemfile gem 'active_model_serializers' install bundle in terminal bundle install Set the ActiveModelSeriali...

For a simple circle: UIBezierPath* ovalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(0,0,50,50)]; [UIColor.grayColor setFill]; [ovalPath fill]; Swift: let ovalPath = UIBezierPath(ovalInRect: CGRect(x: 0, y: 0, width: 50, height: 50)) UIColor.grayColor().setFill() ovalPath.fill...