Tutorial by Examples: l

To reference a variable in a query, add a colon (:) before the variable name. Datetime targetDate = Datetime.now().addDays(-7); List<Lead> recentLeads = [SELECT Id FROM Lead WHERE CreatedDate > :targetDate]; string targetName = 'Unknown'; List<Contact> incompleteContacts = [SELE...

When assigning to a single object, a query that returns anything other than a single row will throw a QueryException. try { Account a = [SELECT Id FROM Account WHERE Name = 'Non-existent Account']; } catch (QueryException e) { // List has no rows for assignment to SObject } try { ...

One big problem is that valuable named routes is not supported by Express out of the box. Solution is to install supported third-party package, for example express-reverse: npm install express-reverse Plug it in your project: var app = require('express')(); require('express-reverse')(app); ...

Intent: Separate the construction of a complex object from its representation so that the same construction process can create different representations Builder pattern is useful when you have few mandatory attributes and many optional attributes to construct a object. To create an object with dif...

Template method pattern is a behavioral design pattern that defines the program skeleton of an algorithm in an operation, defering some steps to subclasses. Structure: Key notes: Template method uses Inheritance The Template method implemented by the base class should not be overridden. In t...

Often you will want to perform asynchronous operations in parallel. There is direct syntax that supports this in the async/await proposal, but since await will wait for a promise, you can wrap multiple promises together in Promise.all to wait for them: // Not in parallel async function getFriend...

entry = tk.Entry(parent, width=10) entry.insert(0, "Hello, World!")

The value of an entry widget can be obtained with the get method of the widget: name_entry = tk.Entry(parent) ... name = name_entry.get() Optionally, you may associate an instance of a StringVar, and retrieve the value from the StringVar rather than from the widget: name_var = tk.StringVar() ...

// A simple class hierarchy that uses the visitor to add functionality. // class VehicleVisitor; class Vehicle { public: // To implement the visitor pattern // The class simply needs to implement the accept method // That takes a reference to a visitor object tha...

The visitor Pattern can be used to traverse structures. class GraphVisitor; class Graph { public: class Node { using Link = std::set<Node>::iterator; std::set<Link> linkTo; public: void accept(GraphVisito...

Since Java lambdas are closures, they can "capture" the values of variables in the enclosing lexical scope. While not all lambdas capture anything -- simple lambdas like s -> s.length() capture nothing and are called stateless -- capturing lambdas require a temporary object to hold the...

Modules can be required without using relative paths by putting them in a special directory called node_modules. For example, to require a module called foo from a file index.js, you can use the following directory structure: index.js \- node_modules \- foo |- foo.js \- package.json ...

<?php use Symfony\Bundle\FrameworkBundle\Controller\Controller; use Symfony\Component\HttpFoundation\Request; class TestController extends Controller { //Inject Request HTTP Component in your function then able to exploit it public function myFunctionAction(Request $request) {...

Objective-C UILabel *label = [[UILabel alloc] init]; label.highlighted = YES; label.highlightedTextColor = [UIColor redColor]; Swift let label = UILabel() label.highlighted = true label.highlightedTextColor = UIColor.redColor() Swift 3 let label = UILabel() label.isHighlighted = true ...

If you like to show the dialog without the close button (i.e. the x button in the upper-right corner of the dialog), perhaps because you want to force the user to select one of options or buttons in the dialog itself: 1- Give your dialog a CSS class: $("#selector").dialog({ closeOnE...

Download: To set up WebSphere Liberty, download the latest zip from WASdev.net. Layout: Once you have the zip, extract it to any location on your file system. The basic layout of a Liberty install is the following: wlp/ # WLP_INSTALL_DIR bin/ # location of scrip...

Usage: $ nodetool repair [-h | -p | -pw | -u] <flags> [ -- keyspace_name [table_name]] Default Repair Option $ nodetool repair This command will repair the current node's primary token range (i.e. range which it owns) along with the replicas of other token ranges it has in all tables a...

System.Obsolete is an attribute that is used to mark a type or a member that has a better version, and thus should not be used. [Obsolete("This class is obsolete. Use SomeOtherClass instead.")] class SomeClass { // } In case the class above is used, the compiler will give the w...

Nesting is great for keeping related selectors together to make it easier for future developers to understand your code. The parent selector, represented by an ampersand ("&") can help do that in more complex situations. There are several ways its can be used. Create a new selector th...

This are the tools you need to build SFML for Android on a Windows Machine CMake Git Android SDK Android NDK Apache Ant MinGW (msys basic) Java jre Java jdk Android USB Driver (Download: http://adbdriver.com/ ) Make sure you've installed all tools (Tools -> Android SDK Tools / Platf...