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To build a Rails application that will be an API server, you can start with a more limited subset of Rails in Rails 5. To generate a new Rails API app: rails new my_api --api What --api does is to remove functionality that is not needed when building an API. This includes sessions, cookies, ass...

Sometimes you may need to validate record only under certain conditions. class User < ApplicationRecord validates :name, presence: true, if: :admin? def admin? conditional here that returns boolean value end end If you conditional is really small, you can use a Proc: class ...

In cryptography, encryption is the process of encoding messages or information in such a way that only authorized parties can access it. Source: Encryption - Wikipedia

Functions that are O(n) increase the number of operations linearly, as the input gets very large. A simple example of a function that is O(n) would be the linear search algorithm, which runs once for the size of the input. The following pseudo-code would be O(n), because it will always be bounded ...

We can add Kendo-UI grid in HTML5/Javascript, ASP.NET MVC, JSP and PHP project/application. Please follow below steps to add kendo-UI grid in HTML5 page. Create empty html5 page. Include kendo.common.min.css and kendo.default.min.css. Add a link tag within the head tag. Kendo-UI li...

Consider the following naive method for adding two positive numbers using recursion: public static int add(int a, int b) { if (a == 0) { return b; } else { return add(a - 1, b + 1); // TAIL CALL } } This is algorithmically correct, but it has a major problem. ...

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General syntax: DATEADD (datepart , number , datetime_expr) To add a time measure, the number must be positive. To subtract a time measure, the number must be negative. Examples DECLARE @now DATETIME2 = GETDATE(); SELECT @now; --2016-07-21 14:39:46.4170000 SELECT DAT...

General syntax: DATEDIFF (datepart, datetime_expr1, datetime_expr2) It will return a positive number if datetime_expr is in the past relative to datetime_expr2, and a negative number otherwise. Examples DECLARE @now DATETIME2 = GETDATE(); DECLARE @oneYearAgo DATETIME2 = DATEADD(YEAR, -1, @now...

A CSS rule consists of a selector (e.g. h1) and declaration block ({}). h1 {}

To start using Spring data JPA, you must include the dependency in your project with the one of Spring core, all together. If you're using Maven as dependency management system (replace version-number for the version you want to use): <dependencies> <dependency> <groupI...

This attribute applies a version to the assembly. [assembly: AssemblyVersion("1.0.*")] The * character is used to auto-increment a portion of the version automatically every time you compile (often used for the "build" number)

Codeigniter may be configured to run more than one project without duplicating CI core files. It's possible by splitting CI Application side. For example let's take project of website, which contains front-end and back-end Content Management System (CMS) applications. In this case CI folder struct...

Your code in source control has version numbers either by default (SVN ids or Git SHA1 hashes) or explicitly (Git tags). Rather than manually updating versions in AssemblyInfo.cs you can use a build time process to write the version from your source control system into your AssemblyInfo.cs files and...

A higher-order function is one that takes another function as an argument or returns a function (or both). This is commonly done with lambdas, for example when passing a predicate to a LINQ Where clause: var results = data.Where(p => p.Items == 0); The Where() clause could receive many diffe...

This example shows how a MongoDB collection can be displayed in a React component. The collection is continuously synchronized between server and client, and the page instantly updates as database contents change. To connect React components and Meteor collections, you'll need the react-meteor-data...

Publications can be merged on the client, resulting in differently shaped documents within a single cursor. The following example represents how a user directory might publish a minimal amount of public data for users of an app, and provide a more detailed profile for the logged in user. // client...

Then go into the mongo shell and initiate the replica set, like so: meteor mongo > rs.initiate() PRIMARY> rs.add("mongo-a") PRIMARY> rs.add("mongo-b") PRIMARY> rs.add("mongo-c") PRIMARY> rs.setReadPref('secondaryPreferred')

PMF FOR THE BINOMIAL DISTRIBUTION Suppose that a fair die is rolled 10 times. What is the probability of throwing exactly two sixes? You can answer the question using the dbinom function: > dbinom(2, 10, 1/6) [1] 0.29071 PMF FOR THE POISSON DISTRIBUTION The number of sandwhich ordered in ...