Tutorial by Examples: di

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...

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...

If you use an index that is sorted the way you would retrieve it, the SELECT statement would not do additional sorting when in retrieval. CREATE INDEX ix_scoreboard_score ON scoreboard (score DESC); When you execute the query SELECT * FROM scoreboard ORDER BY score DESC; The database system ...

Layout Unity basic editor will look like below. Basic functionalities of some default windows/tabs are described in the image. Linux Layout There is a little difference in menu layout of linux version, like the screenshot below, Basic Usage Create an empty GameObject by right clicking in th...

Occasionally you'd want to catch an exception and throw it from a different thread or method while preserving the original exception stack. This can be done with ExceptionDispatchInfo: using System.Runtime.ExceptionServices; void Main() { ExceptionDispatchInfo capturedException = null; ...

If you are able to download an update of Android Studio, but after it restarts nothing happens, check out the following example: After the patch was downloaded and Android Studio closed, open the terminal Go to your android studio folder, e.g. cd ~/android-studio Go to bin subfolder: cd bin ...

.NET Framework defines a interface for types requiring a tear-down method: public interface IDisposable { void Dispose(); } Dispose() is primarily used for cleaning up resources, like unmanaged references. However, it can also be useful to force the disposing of other resources even though ...

First, import the libraries that work with files: from os import listdir from os.path import isfile, join, exists A helper function to read only files from a directory: def get_files(path): for file in listdir(path): full_path = join(path, file) if isfile(full_path): ...

If you need to call an Objective-C method from C code, you have two ways: using objc_msgSend, or obtaining the IMP (method implementation function pointer) and calling that. #import <objc/objc.h> @implementation Example - (double)negate:(double)value { return -value; } - (doubl...

// *** Find Distinct object ids of array *** NSLog(@"Distinct id : %@",[array valueForKeyPath:@"@distinctUnionOfObjects.id"]);

It is usually not a good idea to mix signed and unsigned integers in arithmetic operations. For example, what will be output of following example? #include <stdio.h> int main(void) { unsigned int a = 1000; signed int b = -1; if (a > b) puts("a is more than b&quot...

There are multiple ways to set a key's object in an NSDictionary, corresponding to the ways you get a value. For instance, to add a lamborghini to a list of cars Standard [cars setObject:lamborghini forKey:@"Lamborghini"]; Just like any other object, call the method of NSDictionary th...

There are multiple ways to get an object from an NSDictionary with a key. For instance, to get a lamborghini from a list of cars Standard Car * lamborghini = [cars objectForKey:@"Lamborghini"]; Just like any other object, call the method of NSDictionary that gives you an object for a ...

Represents a thread-safe collection of key/value pairs that can be accessed by multiple threads concurrently. Creating an instance Creating an instance works pretty much the same way as with Dictionary<TKey, TValue>, e.g.: var dict = new ConcurrentDictionary<int, string>(); Ad...

First the setup for the example: import datetime as dt from sqlalchemy import Column, Date, Integer, Text, create_engine, inspect from sqlalchemy.orm import sessionmaker from sqlalchemy.ext.declarative import declarative_base Base = declarative_base() Session = sessionmaker() class User(B...

In SQLAlchemy core, the result is RowProxy. In cases where you want an explicit dictionary, you can call dict(row). First the setup for the example: import datetime as dt from sqlalchemy import ( Column, Date, Integer, MetaData, Table, Text, create_engine, select) metadata = MetaData() u...

There are multiple ways to populate an array. Directly 'one-dimensional Dim arrayDirect1D(2) As String arrayDirect(0) = "A" arrayDirect(1) = "B" arrayDirect(2) = "C" 'multi-dimensional (in this case 3D) Dim arrayDirectMulti(1, 1, 2) arrayDirectMulti(0, 0, 0...

JSON data can also be read from files. Let's assume we have a file called data.json with the following content: [ { "Name" : "John Doe", "Standard" : 4 }, { "Name" : "Peter Parker", "Standard" : ...

In Android there is a default options menu, which can take a number of options. If a larger number of options needs to be displayed, then it makes sense to group those options in order to maintain clarity. Options can be grouped by putting dividers (i.e. horizontal lines) between them. In order to a...