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

  Sort an array with only one local variable

Array sorting algorithm question is frequently asked during technical interviews. There are lots of sort algorithms including bubble sort, selection sort, insertion sort, quick sort, merge sort etc. Usually interviewees will be asked to implement sort algorithms. But have you ever been asked to sort an array which you are allowed to define ONLY ONE local variable in your algorithm?  Bubble sort can be used to do this actually. Normally a bubble sort algorithm may need three local ...

   JAVASCRIPT,ALGORITHM,SORTING,BUBBLE SORT     2016-10-07 09:46:49

  Bad code plagues business applications, especially Java ones

A new study examining 365 million lines of code in 745 applications identifies bad coding practices that affect security, performance and uptime, with Java Enterprise Edition applications having the greatest number of problems. Cast Software, which makes tools that automate the analysis of business applications, examined programs written in Java-EE, .NET, ABAP, C, C++, Cobol, Oracle Forms, and Visual Basic, used across a wide range of industries from energy and financial services to IT co...

   Program,Security,Defects,Java     2011-12-09 07:42:51

  Is Mobile App Required For Your Business?

Having a mobile app for your business is the latest trend. Every business, large or small is aiming for developing a mobile app to attract customers and boost the sales. Products or services offered by the business do not matter in this case.  The main purpose is to keep your users updated and engaged. An app is a perfect tool for generating new customers too. The statistics reveals that numbers of mobile internet users are more than the desktop users. It clearly means that businesses must ...

   App Development Services, Outsource Android App Development, Android App Development Experts     2015-03-05 00:47:46

  Android create button tutorial

This tutorial assumes that you already have an activity and are using an XML layout. Open the layout XML and add the button element.  Assign an ID with the “@+id” operator.  The + tells Android to generate an ID for this element so that you can reference it in your Java files. This is an example. Your layout and text elements will probably be very different. In this example case, the ID of the button is “close”. <Button android:id="@+id/close" android:lay...

   Android,Simulator,Button,XML,Tutorial     2014-11-07 08:30:10

  Is programmer really profession for youth only?

- dedicated to the new programmers just into the workplace.

One young Chinese friend asked me: is programmer meant only for less experienced youth? Should I consider transition once if I work on it until 30 years old?

   Programmer,Youth,Product,Project,Career,Analysis     2012-03-18 07:06:44

  Beauty of code : How to write graceful PHP code

Writing good code is an art. In order to achieve this, it is necessary to develop good programming habits at the beginning. Good programming habits not only contributes to the early project design (modular),but also allows you to the code easier to understand, so that the maintenance of the code is easier. Bad programming habits will result in more code bugs, and will make future maintenance work difficult. We introduce some good programming habits taking PHP as example. Hope this will help you....

   PHP,Good code     2012-08-26 12:23:03

  About C++ comma operator precedence

When learning programming language, we will always have one topic about the operator precedence. Since there are many operators can be used in one expression, there should be some rules regarding which operation can happen first so that the compiler or interpreter can handle them correctly. One rule of programming with expression is using as much as brackets as you can to avoid unexpected results. Here we refer one problem we see online about the comma operator in C++. The following program has ...

   comma,precedence     2012-11-12 10:25:00

  Top 8 website operation laws

As a website operator, in addition to have some necessary professional knowledge to master a website, such as prototype planning, interaction design, SEO, as well as basic html code, you should also know more about some of the theories which are good for site operations to ensure that the site can be long-term, stable. 1. Law of 250 Girard thinks every person knows at least 250 people. If you win the goodwill of a customer, it means you win the goodwill of 250 individuals; Conversely, if you off...

   Website management,Rules     2012-09-13 20:55:50

  10 design flaws of JavaScript

JavaScript's design took only ten days. Moreover, the designer didn't want to design it initially, he just wanted to complete the task assigned by company. It is now a very powerful client side programming language used in almost all the websites. It's an excellent language, but it also has some flaws. 1. Not suitable for large projects JavaScript doesn't have namespace, it's hard to be modular, there is no standard for putting codes in multiple source files. It allows defining functions with th...

   JavaScript, Design flaw, Object     2012-11-29 11:39:35