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  Understanding database, instance and schema in Oracle database

Oracle database is the most popular database system among enterprises. To start working on Oracle database, some concepts must be understood first. They include database, instance, schema and user etc. And among these concepts, some have different meanings from those in other database systems such as MS SQL, MySQL, DB2. On the web, there are already some good posts which explain different concepts such as Ask Tom's database vs instances, Difference between database vs user vs schema. In this pos...

   DIFFERENCE,DATABASE,ORACLE DATABASE,INSTANCE,SCHEMA,USER     2016-12-14 23:30:56

  China has blocked Wikipedia again

Recently lots of Chinese found they experienced problems while trying to access Wikipedia, the world's largest and most well-known free encyclopedia. It turns out that the notorious Chinese GFW(Great Firewall) is playing the critical role here. It blocks the Chinese version of Wikipedia. The reason why the Chinese version of Wikipedia is blocked is said to be that Wikipedia has changed its default protocol from HTTP to HTTPS. This change made it difficult for the GFW to filter some sensiti...

   CHINA,WIKIPEDIA,GFW,BLOCKED,NEWS     2015-12-05 19:04:12

  Some laws of interactive design

The well known quote from Alan Cooper is   Conforming to the standard unless there is a better choice. There are some best practices in interaction design. How many do you know? 1. Fitts' Law The time from one start point to target point is determined by two parameters: The distance to the target and the size of the target. )D and W in above picture), the formula is : T=a+blog2(D/W+1). It was first proposed by Paul Fitts, it is mathematical model used to predict the time from any poin...

   interaction design, laws, Fitts' law     2012-11-16 11:25:24

  Chrome to provide native image lazyload support

Previously we have introduced how Medium achieved loading images lazily, basically what they did was using lots of HTML tags and CSSs to change the images at different stage. It needs lots of code to do this. With the high demand of this feature for resource consumption and performance consideration, Chrome is now working on a feature to provide native support for loading images/iframes lazily. This feature is named lazyload. lazyload will allow three values: auto: the default behavior of ...

   CHROME,LAZYLOAD,IMAGE,IFRAME     2018-09-22 23:04:35

  Create customized GitHub profile page

How long have you been using GitHub? Have you ever wondered whether one can customize his profile page with some fancy looking? Indeed GitHub allows developers to customize profile page through a secret repository. The secret is to create a repository with the same name as your GitHub username. And you will be granted into the work of customizing your own profile page. In this post, we will show a simple walk through on how to create it. Create secret repository As indicated by the term secret r...

   GITHUB,CUSTOMIZED PROFILE,SECRET REPOSITORY     2020-10-18 03:02:42

  GCC is compiled with C++ compiler

On 15 Aug, 2012, GCC merged a patch--Merge from cxx-conversion branch . This means GCC will be compiled with C++ compiler in the future, it also means that GCC will be implemented using C++. You may have following two puzzles: Why does GCC turn to C++? Without C++ compiler, how can we compile C++ codes? Why using C++? In GNU's C++ Conversion, we can find this description in the background section: Whether we use C or C++, we need to try to ensure that interfaces are easy to understan...

   GCC,C++,Compiler     2012-09-04 02:36:06

  Have you used these JavaScript libraries before?

Are you a vanilla JavaScript developer or a JavaScript library lover?  If you are a vanilla JavaScript developer, please feel free to step away silently because you may not get what you want, but if you are a library or framework lover, please bookmark this page as what we list below are what you may use in the future. There are tons of JavaScript libraries created to ease the headache of developers who have to deal with different browsers on different devices. You may use some of them befo...

   JavaScript,Framework,Library     2014-09-27 22:06:55

  Implementation of +,-,*,/ with bitwise operator

There is a question asked on Stackoverflow : Divide a number by 3 without using *,/,+,-,% operators. This question is an Oracle interview question. Some people give excellent answers. You can go there and take a look. Usually we need to use bitwise operators to do this kind of implementations. Here I want to show you ways to implement +,-,*,/ with bitwise operators. A bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. It is a fast, pr...

   Bitwise operator,Shift,Add,Subtract,Multiplication,Division     2012-08-05 01:52:47

  Concurrency vs Parallelism

Concurrency and parallelism are two related concepts which deal with executing tasks "simultaneously". From Sun's Multithreaded Programming Guide: Concurrency: A condition that exists when at least two threads are making progress. A more generalized form of parallelism that can include time-slicing as a form of virtual parallelism. Parallelism: A condition that arises when at least two threads are executing simultaneously. These two definitions are too formal to be understood easily. On t...

   Concurrency,Parallelism,Thread     2013-08-07 23:42:33

  Products born for Cloud

Cloud computing has become increasingly popularity among companies. It greatly saves the investment of infrastructure and training with everything is running on cloud, it also improves the accessibility and flexibility of service provided by companies. With its popularity, many products are born or becoming popular to help build and move the apps to the cloud. Some well known names of these products are Vagrant, Docker/LXC, Chef and OpenStack. These tools can help create, test and deploy applica...

   Cloud,Openstack,Docker,Vargrant,LXC,Chef     2015-01-25 02:27:11