Tutorial by Examples: d

node_redis, as you may have guessed, is the Redis client for Node.js. You can install it via npm using the following command. npm install redis Once you have installed node_redis module you are good to go. Let’s create a simple file, app.js, and see how to connect with Redis from Node.js. app...

Checking the Existence of Keys Sometimes you may need to check if a key already exists and proceed accordingly. To do so you can use exists() function as shown below: client.exists('key', function(err, reply) { if (reply === 1) { console.log('exists'); } else { cons...

C99 In 1994 more readable alternatives to five of the trigraphs were supplied. These use only two characters and are known as digraphs. Unlike trigraphs, digraphs are tokens. If a digraph occurs in another token (e.g. string literals or character constants) then it will not be treated as a digraph,...

Azure SQL Database has different editions and performance tiers. You can find version, edition (basic, standard, or premium), and service objective (S0,S1,P4,P11, etc.) of SQL Database that is running as a service in Azure using the following statements: select @@version SELECT DATABASEPROPERTYEX...

You can scale-up or scale-down Azure SQL database using ALTER DATABASE statement: ALTER DATABASE WWI MODIFY (SERVICE_OBJECTIVE = 'P6') -- or ALTER DATABASE CURRENT MODIFY (SERVICE_OBJECTIVE = 'P2') If you try to change service level while changing service level of the current database is sti...

You can create a secondary replica of database with the same name on another Azure SQL Server, making the local database primary, and begins asynchronously replicating data from the primary to the new secondary. ALTER DATABASE <<mydb>> ADD SECONDARY ON SERVER <<secondaryserver&gt...

You can put your azure SQL Database in SQL elastic pool: CREATE DATABASE wwi ( SERVICE_OBJECTIVE = ELASTIC_POOL ( name = mypool1 ) ) You can create copy of an existing database and place it in some elastic pool: CREATE DATABASE wwi AS COPY OF myserver.WideWorldImporters ( SERVICE_OBJECTIV...

Prolog features exceptions, which are part of the Prolog ISO standard. An exception can be thrown with throw/1, and caught with catch/3. The ISO standard defines many cases in which errors must or may be thrown. The standardized exceptions are all of the form error(E,_), where E indicates the erro...

A type error occurs if an argument is not of the expected type. Examples of types are: integer atom list. If the predicate is of the expected type, but outside the expected domain, then a domain error is raised. For example, a domain error is admissible if an integer between 0 and 15 is exp...

CLR procedures are not enabled by default. You need to run the following queries to enable CLR: sp_configure 'show advanced options', 1; GO RECONFIGURE; GO sp_configure 'clr enabled', 1; GO RECONFIGURE; GO In addition, if some CLR module need external access, you should set TRUSTWORTHY pr...

Procedures, functions, triggers, and types written in .Net languages are stored in .dll files. Once you create .dll file containing CLR procedures you should import it into SQL Server: CREATE ASSEMBLY MyLibrary FROM 'C:\lib\MyStoredProcedures.dll' WITH PERMISSION_SET = EXTERNAL_ACCESS PERM...

If you have create .Net class that represents some user-defined type, compiled it into .dll, and imported it into SQL server as an assembly, you can create user-defined function that references this class: CREATE TYPE dbo.Point EXTERNAL NAME MyLibrary.[Name.Space.Point] You need to specify name...

If you have created .Net method in some class, compiled it into .dll, and imported it into SQL server as an assembly, you can create user-defined stored procedure that references method in that assembly: CREATE PROCEDURE dbo.DoSomethng(@input nvarchar(max)) AS EXTERNAL NAME MyLibrary.[Name.Space....

Consider a base class Vehicle and its derived class Car as follows: #import <Foundation/Foundation.h> @interface Vehicle : NSObject { NSString *vehicleName; NSInteger vehicleModelNo; } - (id)initWithName:(NSString *)name andModel:(NSInteger)modelno; - (void)print; @end ...

Mixins can be passed a block of SASS compliant code, which then becomes available within the mixin as the @content directive. @mixin small-screen { @media screen and (min-width: 800px;) { @content; } } @include small-screen { .container { width: 600px; } } And this wou...

// 1.0 function beforeLoad(type, form, request) { nlapiLogExecution("DEBUG", "Before Load", "type=" + type); } // 2.0 /** * @NApiVersion 2.x * @NScriptType UserEventScript * @NModuleScope SameAccount */ define(["N/log"], function (log) { ...

public void Screenshot() throws Throwable{ final byte[] screenshot = ((TakesScreenshot) driver).getScreenshotAs(OutputType.BYTES); scenario.embed(screenshot, "image/png"); // ... and embed it in the report. Thread.sleep(1000); } Alternately public static void captureSc...

Frontend Interface /** * Entity attribute frontend interface * * Frontend is providing the user interface for the attribute * */ interface Mage_Eav_Model_Entity_Attribute_Frontend_Interface { } Source Interface /** * Entity attribute select source interface * * Source is providing ...

This is literally the only thing you need to start using RxJava on Android. Include RxJava and RxAndroid in your gradle dependencies: // use the last version compile 'io.reactivex.rxjava2:rxjava:2.1.1' compile 'io.reactivex.rxjava2:rxandroid:2.0.1' RxAndroid main addition to RxJava is a Sche...

var page = require('webpage').create(); page.open('http://www.google.com', function(status) { console.log("Status: " + status); var title = page.evaluate(function() { return document.title; }); console.log("Loaded page: " + title); phantom.exit(); });