SEARCH KEYWORD -- DATA ENGINEERING

  Select top 3 values from each group in a table with SQL

Yesterday, my friend Liu Bing asked me a question about how to select top 3 values for each person in a database table using SQL. I think this question is interesting and it deserves some thoughts. Here I record down how to solve this issue. Assume we have a table which has two columns, one column contains the names of some people and the other column contains some values related to each person. One person can have more than one value. Each value has a numeric type. The question is we want to se...

   SQL,Correlated query,top 3     2013-05-23 03:21:25

  Guide to use Compass

Sass is one kind of CSS Preprocessor, it can make CSS development simple and maintainable. But to show its real power we may need to have Compass. This article is to introduce Compass. Once you learn Compass, your CSS development efficiency will be largely improved. Here we assume you have mastered the major uses of CSS, if you know Sass, then it's better. It's still ok if you don't know Sass. 1. What is Compass? In simple, Compass it the toolkit of Sass. Sass itself is only a compiler, Compass...

   Compass,CSS,Sass,Tutorial     2012-12-03 13:35:46

  Recover deleted file in Linux EXT3 file system

Environment : CentOS 5.3 x86_64, /dev/sdb1 is the data segment /data0. EXT3 file system. Problem : /data0/tcsql/cankao/phpcws-1.5.0/httpcws.cpp is deleted mistakenly and httpcws.cpp is not backed up. It will take much time to rewrite this program again. So we must recover it back. debugfs is feasible in EXT2 file system, but in EXT3 file system, it's not very useful. There is one open source software called ext3grep which can help us recover deleted file in EXT3 file system. The recovery steps a...

   Linux,EXT3,File recovery     2013-08-16 07:06:45

  What to Know About Windows 11

Windows 11 launched in October, with Microsoft bringing some changes to the operating system. It was the first name change in six years, and the rollout began on October 5. The rollout is being phased on eligible devices.  You can download it if you don’t want to wait for it to be your device’s turn.  Some businesses are opting to defer upgrades to Windows 11, as are some individuals. Others are excited to take advantage. The following are some things to know about impleme...

   MICROSOFT,WINDOWS 11     2021-12-06 10:41:04

  HTTP Streaming and Internet Explorer

In early 2006, Alex Russell posted about a neat hack that the Google Talk team in Gmail use to support Comet in Internet Explorer, a trick which works as far back as IE 5.01. What great news! A reliable way to stream Comet messages to Microsoft’s browsers. If only it were that easy. I have not been alone in the following findings: after connecting the htmlfile ActiveX object as a streaming Comet transport to my Comet server, everything works perfectly for a few messages, but then abruptly...

   IE,Streaming,JavaScript,htmlfile,ActiveX     2011-09-05 04:05:23

  Books for entry level C programmers

In computing, C is a general-purpose programming language initially developed by Dennis Ritchie between 1969 and 1973 at Bell Labs Its design provides constructs that map efficiently to typical machine instructions, and therefore it found lasting use in applications that had formerly been coded in assembly language, most notably system software like the Unix computer operating system.To learn C, we need to read many C books and have many practices. Here we summarize a list of C books which may h...

   C,Book,Beginning     2012-07-26 14:00:51

  Google is developing advanced programming technology to simplify Web application development

Beijing, March 28. According to foreign media reports, Google engineer Alex Russell this week at EclipseCon meeting said the company is now developing lots of advanced programming techniques to simplify Web application development.Russell said, "Web development has come to a critical point, it is becoming a run-time library integration platform." Although Web is very popular compared to some platforms such as Java or Windows, it provides only a relatively original programming capability. A ...

   Google,Web,Dart,Scalability     2012-03-30 06:22:13

  Screen recording in Windows 10

Have you ever wondered how to take screen recording easily on Windows? Normally you would think to download some software online and install it on your machine such as Camtasia. However, many of them are either non-free or uneasy to use. Fortunately, there is a built-in tool provided in Windows 10 which can be used to take simple screen recording plus audio recording. The tool is called the Game Bar which is primarily intended for gamers to take screenshots of their plays and achievements. Don't...

   WINDOWS 10,GAME BAR,SCREEN RECORDING     2018-03-06 11:42:07

  Why Building a Mobile App is Hard

Kent Nguyen has a great article about how building iOS apps takes a lot of work. And, here at Parse, we agree. Making a well-designed app is not a trivial task. Many non-developers hugely underestimate the amount of sweat and tears that goes into a single app. The big component that is overlooked and that Kent stresses is the server component. An app is not an island. Users expect their apps to richly interact with the internet. This means you need to worry about developing code on servers, com...

   Mobile app,Hard,Chanllenges,Platform     2012-02-01 04:45:45

  Open source code libraries suffer from vulnerabilities

A study of how 31 popular open source code libraries were downloaded over the past 12 months found that more than a third of the 1,261 versions of these libraries had a known vulnerability and about a quarter of the downloads were tainted. The study was undertaken by Aspect Security, which evaluates software for vulnerabilities, with Sonatype, a firm that provides a central repository housing more than 300,000 libraries for downloading open source components and gets 4 billion requests pe...

   Open source,Security,Vulnerability     2012-03-28 06:10:19

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