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  How Query Optimizer Works in RDBMS

In a previous post, we discussed how the various relational operators are implemented in relational database systems. If you have read that post, you probably still remember that there are a few alternative implementations for every operator. Thus, how should RDBMS determine which algorithm (or implementation) to use? Obviously, to optimize the performance for any query, RDBMS has to select the correct the algorithm based on the query. It would not be desirable to always use the same algori...

   DATABASE,DATABASE DESIGN,DATABASE OPTIMIZATION     2019-04-20 07:26:32

  The Essence of Google Dart: Building Applications, Snapshots, Isolates

WÑ–th thousands of programming languages floating around, why is Google introducing Google Dart? What can it possibly add? The short answer: the Google Dart team wanted a language well suited to modern application development, both on the server and the (mobile) client. Some of Dart's features address problems that languages like Java or Javascript have long had. Dart's Snapshots resemble Smalltalk images, allowing (nearly) instant application startup and wi...

   Dart,Google,Client side,Web,Language,Snapshort,Isolate     2011-10-24 11:41:16

  The Five Stages of Hosting

As a proud VPS survivor, I thought it might be fun to write up five common options for hosting a web business, ranked in decreasing order of 'cloudiness'. People who aren't interested in this kind of minutia would be wise to pull the rip cord right here. 1. The Monastery You run your site on an 'application platform' like Heroku, Azure, or Google App Engine. You design your application around whatever metaphors and APIs the service lays out, and in return you are veiled from all t...

   Website hosting,Recommendations,Stages,Advantages     2012-01-30 05:43:42

  Tips for improving PHP efficiency

0. Using single quote to replace double quote to enclose string literal, this will be a bit faster. Because PHP engine will search variables in double quoted string. 1. If a method in class can be declared as static, then make it static, this will be 4 times faster. 2. $row["id"] is 7 times faster than $row[id] 3. echo is faster than print, and you should use multiple parameters instead of string concatenation, i.e use comma(,) instead of dot(.) to concatenate string. For example echo $str1,$str...

   PHP, efficiency, tips     2012-10-01 19:39:06

  Prototypes and Object Orientation

David Chisnall takes a look at the two dominant paradigms in object-oriented languages (classes and prototypes) and discusses the strengths and weaknesses of each.Two terms are quite often confused when describing programming languages:class-based and object-oriented:Simula was the first class-based language. It provided classes (actually implemented using closures) as a means of encapsulating abstract data types.Smalltalk was the first object-oriented language. It provided a...

   Prototype,OOP,Differential,Comparison,Mo     2011-09-02 11:51:26

  Do scientists really need a PhD?

Young scientists at a Chinese genomics institute are foregoing conventional postgraduate training for the chance to be part of major scientific initiatives. Is this the way of the future?The approach to extended postgraduate training varies from country to country. The United States and Europe, for example, have long believed that students need to finish a multiyear programme of postgraduate work before they can fully participate in the front rank of research, whether in industry or acad...

   Career,PhD,Scientist,Relationship,BGI     2012-01-02 08:19:32

  Lessons Learned while Introducing a New Programming Language

I've used a lot of languages (professionally) over the years: (off the top of my head) Cold Fusion, HTML, Javascript, php, SQL, CSS, ASP(classic & .net), C#, Ruby, Flex, Java, & Clojure. Each language has pros and cons. Being a programmer, it's easiest to discuss the cons - and in general I believe it was best said:I hate all programming languages - Matt FoemmelI think it's important to start with this in mind. At some point you're going to hate what you're advocating, so imagine h...

   Experience,New language,Tips,Risk     2012-03-05 05:13:59

  jQuery 2.0 will drop support for some IE6/7/8 oddities

jQuery official website releases its road map for the future jQuery development. This road map reveals that jQuery 1.8 will be released within a month and other consecutive versions will follow the following release plan:jQuery 1.9 (early 2013): many of the interfaces already deprecated in version 1.8 will be removed; some of them will be available as plugins or alternative APIs supported by the jQuery project. IE 6/7/8 will be supported as today.jQuery 1.9.x (ongoing in 2013 and beyond): This v...

   jQuery 2.0,jQuery,IE support     2012-06-29 05:20:27

  5 million units of Galaxy Note II are sold until now

Samsung announced on its official website that the Galaxy Note II sales have exceeded 5 million units, the number of shipments reached 2 million in last 24 days.Galaxy Note II was officially released at the end of August and was on sale at the end of September, equipped with Android 4.1 Jelly Bean system, 5.5 inches HD Super AMOLED screen and a 1.6GHz quad-core Exynos processor.In the first 37 days on sale, Samsung Galaxy Note II had achieved 3 million units of sales,the sales is  three ti...

   Samsung Galaxy Note II,Sale     2012-11-26 11:19:21

  What will the value of Integer.valueOf(127) == Integer.valueOf(127) be in Java?

Do you really understand how Java does the integer comparison? OK, ignore the statements in the post title. What we are interested in is another set of comparison statements. Let's first see below code snippet. public class IntegerComparison { public static void main(String[] args) { Integer a = 127, b = 127; Integer c = 128, d = 128; System.out.println(a == b); System.out.println(c == d); } } What do you think the output will be? Are they both displaying true? You will find out t...

   JAVA,==,EQUALSTO     2018-01-13 22:18:15