Tutorial by Examples: l

This query selects all employees not on the Supervisors table. SELECT * FROM Employees WHERE EmployeeID not in (SELECT EmployeeID FROM Supervisors) The same results can be achieved using a LEFT JOIN. SELECT * FROM Employees AS e LEFT JOIN Supervisors AS s ON s.E...

Definition : When multiple methods with the same name are declared with different parameters, it is referred to as method overloading. Method overloading typically represents functions that are identical in their purpose but are written to accept different data types as their parameters. Factors af...

We can match on lists like any other data type, though they are somewhat unique, in that the constructor for building up lists is the infix function ::. (See the example Creating a list for more on how that works.) matchMyList : List SomeType -> SomeOtherType matchMyList myList = case myL...

Moment is a javascript library that was designed to make working with dates and times less time-consuming and more intuitive. You can easily start using this library by installing it in you web-app by using one of the following guides. Browser You can either download the JS file from the official...

If you're ever dealing with C Binary API's from Perl Code, via the syscall, ioctl, or fcntl functions, you need to know how to construct memory in a C Compatible way. For instance, if you were ever dealing with some function that expected a timespec, you'd look into /usr/include/time.h and find: s...

The procedure describes how to add an Object library reference, and afterwards how to declare new variables with reference to the new library class objects. The example below shows how to add the PowerPoint library to the existing VB Project. As can be seen, currently the PowerPoint Object library...

In addition to the standard makeLenses function for generating Lenses, Control.Lens.TH also offers the makeClassy function. makeClassy has the same type and works in essentially the same way as makeLenses, with one key difference. In addition to generating the standard lenses and traversals, if the ...

String literals imply no escaping or interpolation ( with the exception of quoting string terminators ) print 'This is a string literal\n'; # emits a literal \ and n to terminal print 'This literal contains a \'postraphe '; # emits the ' but not its preceding \ You can use alternative quoting...

Double-quoted strings use interpolation and escaping – unlike single-quoted strings. To double-quote a string, use either double quotes " or the qq operator. my $greeting = "Hello!\n"; print $greeting; # => Hello! (followed by a linefeed) my $bush = "They misunderestimat...

In Haskell, data types can have arguments just like functions. Take the Maybe type for example. Maybe is a very useful type which allows us to represent the idea of failure, or the possiblity thereof. In other words, if there is a possibility that a computation will fail, we use the Maybe type ther...

We have a sample Spring boot application which stores user data in MongoDB and we are using Rest services to retrieve data First there is a domain class i.e. POJO @Document public class User{ @Id private String id; private String name; } A corresponding repository based on ...

The publisher-subscriber is a familiar concept given the rise of YouTube, Facebook and other social media services. The basic concept is that there is a Publisher who generates content and a Subscriber who consumes content. Whenever the Publisher generates content, each Subscriber is notified. Subsc...

Step 1. Install Java 7 or 8 Step 2. Download Apache Kafka at: http://kafka.apache.org/downloads.html For example, we will try download Apache Kafka 0.10.0.0 Step 3. Extract the compressed file. On Linux: tar -xzf kafka_2.11-0.10.0.0.tgz On Window: Right click --> Extract here Step 4. Sta...

Analog to get a collection for a Stream by collect() an array can be obtained by the Stream.toArray() method: List<String> fruits = Arrays.asList("apple", "banana", "pear", "kiwi", "orange"); String[] filteredFruits = fruits.stream() ....

A common pitfall of child classes is that, if your parent and child both contain a constructor(__construct()) method, only the child class constructor will run. There may be occasions where you need to run the parent __construct() method from it's child. If you need to do that, then you will need to...

Instructions on installing Laravel 5.1 on a Linux/Mac/Unix Machine. Before initiating the installation, check if the following requirements are met: PHP >= 5.5.9 OpenSSL PHP Extension PDO PHP Extension Mbstring PHP Extension Tokenizer PHP Extension Let's begin the installation: Inst...

To support a given application, you often create a new role and database to match. The shell commands to run would be these: $ createuser -P blogger Enter password for the new role: ******** Enter it again: ******** $ createdb -O blogger blogger This assumes that pg_hba.conf has been prope...

Table file with header, footer, row names, and index column: file: table.txt This is a header that discusses the table file to show space in a generic table file index name occupation 1 Alice Salesman 2 Bob Engineer 3 Charlie Janitor This is a footer becaus...

A minimal CMake project file that uses Qt5 can be: cmake_minimum_required(VERSION 2.8.11) project(myproject) find_package(Qt5 5.7.0 REQUIRED COMPONENTS Core ) set(CMAKE_AUTOMOC ON) add_executable(${PROJECT_NAME} main.cpp ) target_link_libraries(${PROJECT_NAME} Qt5::C...

In the Project.pro file we add : CONFIG += sql in MainWindow.h we write : #include <QMainWindow> #include <QSql> #include <QDebug> namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget...