Tutorial by Examples: ed

Delete ALL documents with a 'farewell' property set to 'okay'. const MongoClient = require('mongodb').MongoClient; const url = 'mongodb://localhost:27017/test'; MongoClient.connect(url, function (err, db) { if (err) throw new Error(err); db.collection('myCollection').deleteMany(// M...

In this example we have only one object but it is shared between/executed on different threads. Ordinary usage of fields to save state would not be possible because the other thread would see that too (or probably not see). public class Test { public static void main(String[] args) { ...

Reduction is the process of applying a binary operator to every element of a stream to result in one value. The sum() method of an IntStream is an example of a reduction; it applies addition to every term of the Stream, resulting in one final value: This is equivalent to (((1+2)+3)+4) The reduc...

Orthogonal to the JRE versus JDK dichotomy, there are two types of Java release that are widely available: The Oracle Hotspot releases are the ones that you download from the Oracle download sites. The OpenJDK releases are the ones that are built (typically by third-party providers) from the Ope...

A JDK installation and a text editor are the bare minimum for Java development. (It is nice to have a text editor that can do Java syntax highlighting, but you can do without.) However for serious development work it is recommended that you also use the following: A Java IDE such as Eclipse, In...

Tests all polygon sides for intersections to determine if 2 polygons are colliding. // polygon objects are an array of vertices forming the polygon // var polygon1=[{x:100,y:100},{x:150,y:150},{x:50,y:150},...]; // The polygons can be both concave and convex // return true if the 2 polygons ...

Tests if the [x,y] point is inside a wedge. // wedge objects: {cx:,cy:,radius:,startAngle:,endAngle:} // var wedge={ // cx:150, cy:150, // centerpoint // radius:100, // startAngle:0, endAngle:Math.PI // } // Return true if the x,y point is inside the closed wedge function is...

To detect multiple features at once, use the and operator. @supports (transform: translateZ(1px)) and (transform-style: preserve-3d) and (perspective: 1px) { /* Probably do some fancy 3d stuff here */ } There is also an or operator and a not operator: @supports (display: flex) or (display...

JSON is textual format, so it is stored in standard NVARCHAR columns. NoSQL collection is equivalent to two column key value table: CREATE TABLE ProductCollection ( Id int identity primary key, Data nvarchar(max) ) Use nvarchar(max) as you are not sure what would be the size of your JSON ...

Since JSON is stored textual column, you might want to ensure that it is properly formatted. You can add CHECK constraint on JSON column that checks is text properly formatted JSON: CREATE TABLE ProductCollection ( Id int identity primary key, Data nvarchar(max) CONSTRAINT [Data shoul...

You can expose values from JSON column as computed columns: CREATE TABLE ProductCollection ( Id int identity primary key, Data nvarchar(max), Price AS JSON_VALUE(Data, '$.Price'), Color JSON_VALUE(Data, '$.Color') PERSISTED ) If you add PERSISTED computed column, value from JSON tex...

If you can use memory-optimized tables, you can store JSON as text: CREATE TABLE ProductCollection ( Id int identity primary key nonclustered, Data nvarchar(max) ) WITH (MEMORY_OPTIMIZED=ON) Advantages of JSON in in-memory: JSON data is always in memory so there is no disk access Ther...

OPENJSON function parses collection of JSON objects and returns values from JSON text as set of rows. If the values in input object are nested, additional mapping parameter can be specified in each column in WITH clause: declare @json nvarchar(4000) = N'[ {"data":{"num":&quot...

JSON may have complex structure with inner arrays. In this example, we have array of orders with nested sub array of OrderItems. declare @json nvarchar(4000) = N'[ {"Number":"SO43659","Date":"2011-05-31T00:00:00", "Items":[{"Price"...

Using the overflow property with a value different to visible will create a new block formatting context. This is useful for aligning a block element next to a floated element. CSS img { float:left; margin-right: 10px; } div { overflow:hidden; /* creates block formatting context...

Its possible to change *.vmoptions and idea.properties files without editing them in the PhpStorm installation folder. Follow the steps below: Step 1: Run Help - Edit Custom VM Options... Step 2: Confirm the creation of the configuration file, if prompted Step 3: Add following lines if yo...

When you are in a controllerAction And have a POST request coming in, but want to redirect it, to a different route, while still maintaining the POST method and the request object, you can use the following: return $this->redirectToRoute('route', array( 'request' => $request, ), 307); ...

Subdomain-based routing can be handled in Symfony using host parameter. For example, _locale parameter can be used as subdomain value. Assuming locale: en domain: somedomain.com parameters are defined in parameters.yml config file, route would be: /** * @Route( * "/", * ...

If Sitecore is setup in a CM-CD enviornment there could be a need to fire events on CD server when CM events are fired. The example could be firing publish:end:remote on CD when content editors done publish on CM. In order to make sure that events are firing the following steps are required to be ...

Python follows PEMDAS rule. PEMDAS stands for Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction. Example: >>> a, b, c, d = 2, 3, 5, 7 >>> a ** (b + c) # parentheses 256 >>> a * b ** c # exponent: same as `a * (b ** c)` 7776 >>...