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  mysql – connection example

Mysql is a database, and to gain access to the data within C++ you will need to be able to “talk” to the database via queries (just like on the mysql command line interface e.g. select * from tablename), the connection process is very similar to the command line interface you will need to supply connection details as in hostname (localhost normally), username, password, database to use and also there are other details that you can pass e.g port number more information can be gained f...

   C++,Database,MySQL,Connection,Example     2011-10-29 00:42:10

  Empty slice vs nil slice in GoLang

In Go, there is a type called slice which is built on top of array. It's a very convenient type when we want to handle a group of data. This post will explain a subtle but tricky difference between empty slice and nil slice. A nil slice is a slice has a length and capacity of zero and has no underlying array. The zero value of slice is nil. If a slice is declared like below, it is a nil slice. package main import "fmt" func main() { var a []string fmt.Println(a == nil) } The output will be t...

   GOLANG,JSON,EMPTY SLICE,NIL SLICE     2018-10-18 09:25:21

  Cache Reheating - Not to be Ignored

An important aspect to keep in mind with databases is the cost of cache reheating after a server restart. Consider the following diagram which shows several cache servers (e.g., memcached) in front of a database server.This sort of setup is common and can work quite well when appropriate; it removes read load from the database and allows more RAM to be utilized for scaling (when the database doesn’t scale horizontally). But what happens if all the cache servers restart at the same time, s...

   Database,Cost,Cache reheating,Advice     2011-09-21 09:47:29

  How to let Google index AJAX contents?

There are lots of websites containing only one page now with the popularity of AJAX. The website will load different contents according to different inputs from users. This approach provides good user experience and it also helps save bandwidth, the drawback is that AJAX contents are not easy to be indexed by search engines. For example, if you have a website: http://example.com Users can see different contents with the appended # structure in the URL: http://example.com#1 http://example.com#2 h...

   AJAX,Search engine,Google,History     2013-07-16 00:47:14

  Recursive class initialization in Java

When a Java class is referenced and initialized, it has to go through the loading and linking first. Once the loading and linking complete successfully. The class will be initialized. The static variables and constant variables will be initialized during this process. Once the class is initialized, it is ready for use. If when class A is initialized and it is referencing a class B, the class B will also get initialized. But what will happen if class B is referencing class A as well? This is call...

   Java,JVM,class initialization,static final     2015-04-15 21:04:29

  An Object is not a Hash

Following my article A String is not an Error, I want to bring attention to an issue that similarly applies to JavaScript in general, but has special relevance in the Node.JS environment. The problem boils down to the usage of {} as a data-structure where the keys are supplied by untrusted user input, and the mechanisms that are normally used to assert whether a key exists. Consider the example of a simple blog created with Express. We decide to store blog posts in memory in a {}, indexed ...

   Object,Hash,Node.js,JavaScript     2012-01-19 10:16:10

  Simple Animation in the HTML5 Canvas Element

HTML5 is generating all kinds of buzz these days. Some of the buzz is about HTML5 being a replacement for Adobe’s Flash. I don’t think it’s there yet but it’s certainly on the way to changing the way content is presented on the web. This is a description of a very simple animation in an HTML5 canvas element. It is coded for readability and not for optimized operation. We’ll add a canvas element to a web page and then use javascript to draw on it. We will...

   HTML5,Canvas,Animation,Sample code     2011-07-01 10:20:08

  Remote execute command in Java example

Frequently there is a need to logon to a remote system and run some commands or programs to get the output, many software can serve this purpose such as putty and gitshell.These software usually provide secure access to the remote system. But have you ever wondered what to do if you need to run commands on many different systems at the same time and get all these results back at a single place? Especially in big data era, many tasks may run on different distributed systems and you want o have a ...

   JSch, Example, Distributed system, SSH2     2014-12-12 03:20:19

  Using MySQL Connector/C++ with Visual Studio 2010

MySQL Connector/C++ is one of the latest connectors for MySQL, developed by Sun Microsystems. The MySQL connector for C++ provides an object-oriented application programming interface (API) and a database driver for connecting C++ applications to the MySQL Server.When we want to build a database application with C++ using Visual Studio 2010, we may use the MySQL Connector/C++, but sometimes we may encounter different errors, either compile or runtime error. After tried many times, I finally made...

   MySQL Connector,C++,Visual Studio 2010,VS2010     2012-06-01 13:52:20

  Data as code

What is a good command line parser API? A good command line parser should consider below 5 aspects: Support convenient help information generation Support sub commands, for example, git has push,pull,commit sub commands. Support single character option, word option, flag option and option with parameter. Support default option, for example, if no -port is set, set it as 5037 Support usage model, for example, tar's -c and -x is mutually exclusive, they belong to different usage models. Here are...

   Command line,API     2013-08-08 22:40:36

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