Today's Question:  What does your personal desk look like?        GIVE A SHOUT

SEARCH KEYWORD -- Compressed index

  Understanding How is Data Stored in RDBMS

We all know that DBMS (database management system) is used to store (a massive amount of) data. However, have you ever wondered how is data stored in DBMS? In this post, we will focus on data storage in RDBMS, the most traditional relational database systems. Physical Storage Data can be stored in many different kinds of medium or devices, from the fastest but costy registers to the slow but cheap hard drives, or even magnetic tapes. Nowadays, IaaS providers such as AWS...

   RDBMS,DATABASE     2019-02-04 09:25:36

  Why should we keep column as NOT NULL instead of NULL in MySQL?

Keep table column as NOT NULL instead of NULL except in some special cases. This statement is cited by many articles of MySQL optimization, but they don't say why we should do this. Here we discuss about this. First why are there many people using NULL when defining table? The reasons may be: NULL the the default when defining table, the rookies or people who don't want to have much troubles will keep this default setting Many people think NOT NULL will require more space Many people don't want...

   MySQL,NULL,reason     2012-10-27 03:21:27

  Gmail supports 10 GB attachment after integrating with Google Drive

Google today announced Gmail allows users to send attachment up to 10GB after integrating with Google Drive, the attachment size can be 400 times larger than traditional mail attachment size.Google also added another feature recently, it will pop up a separate window when writing new email. The integration of Gmail with Google Drive will introduce one Google Drive button at the bottom of the popup window, as a solution for sending large attachment.At the same time, because the attachment will b...

   Google Drive, Gmail,SkyDrive,attachment     2012-11-28 11:12:56

  Jelly Bean distribution reaches 0.8% in all Android distributions

Jelly Bean (Android 4.1) is a surprise Google I/O conference bringing to us. After three weeks, Google official statistics said Jelly Bean distribution had reached 0.8% in all Android distributions.The latest Android ecosystem data shows Jelly Bean has a very good start, HSPA+ version of Galaxy Nexus can upgrade the system to Android 4.1(Jelly Bean) began in early July. The Ice Cream Sandwich system distribution rose to 15.8% from 10.9%, it became the second largest system version  followin...

   Jelly Bean,Distribution,Share     2012-08-03 15:11:27

  Remove browse button from input type=file

In Web 2.0 era, many websites will ask the user to upload their avatar when creating their profile. In HTML, the input control we should use is input="file". This is a file control provided by the browser vendor and it should be ran in a sandbox for security consideration. Browsers don't provide ways to choose file from local and upload to the remote server without the input="file" control.  There is one annoying part about the input="file", which is a default button named "Choose File" or...

   file,html,browse,remove browse button     2015-07-12 05:17:51

  Why exception would be thrown when deleting element while looping through HashMap in Java

HashMap and other Collection types are frequently used in Java application programming. This post will explain why exception would be thrown when deleting element with Map.remove() while looping through a Map using Iterator. This issue would also occur to other Collection types such as Set, List. Below is a sample code snippet demonstrating the exception thrown. Map<String,String> map = Collections.synchronizedMap(new TreeMap<String,String>()); map.put("key1","value1"); map.put("ke...

   JAVA,HASHMAP,CONCURRENTMODIFICATIONEXCEPTION     2018-06-30 12:49:09

  Interview Programming Problems Done Right

Introduction Why 37signals Doesn't Hire Programmers Based on Brainteasers and my comment on HN generated a lot of responses, so much so that I'm writing this post to properly explain the essence of a good (IMHO) interview programming problem. Pascal's Triangle Pascal's Triangle is a shortcut for getting coefficients most often used binomial probability. The root element is 1. Every other element is the sum of the one or two above it (diagonally left and diagonally right). There are severa...

   Interview,Programming problem,Pascal,Triangle     2012-01-06 09:46:43

  mysql_fetch_array(),mysql_fetch_assoc() and mysql_fetch_row()

In PHP MySQL mannual. There are three functions which need to be clarified for some users who may get confused when choosing which one to use to get the result. mysql_fetch_array() : by seeting the different parameters, there are three ways to return the result set. MYSQL_ASSOC(Result set with field names as the associative indexs.It means you can use the field name as the index to get value of the specified cell). MYSQL_NUM(Result set with field names as the number indices). Or MYSQL_BOTH(...

   PHP,MySQL,resultset,comparison,mysql_fet     2011-08-05 04:53:09

  Understand Virtual DOM

With the popularity of React, the internals and implementation of Virtual DOM has becoming top discussed topic in tech communities and interviews. This post will give an introduction of Virtual DOM and how to implement a simple Virtual DOM logic. How to understand Virtual DOM In early days, front end developers would update a webpage view based on the data status change(usually after making AJAX call). But it brings performance penalties when there is frequent update as it would cause page reflo...

   JAVASCRIPT,DOM,VIRTUAL DOM     2019-12-07 23:43:04

  10 super useful PHP snippets you probably haven’t seen

When working with PHP, it is very useful to have a “toolbox” of handy functions and code snippets that can save lots of time when needed. Today, I’m going to show you 10 super useful code snippets that you probably never heard of. Text messaging with PHP using the TextMagic API If for some reason, you need to send text messages to your clients cell phones, you should definitely have a look to TextMagic. They provide an easy API which allow you to send SMS to cell...

   PHP,Code,Snippet,Useful code segment     2012-01-19 11:07:16

RECENT