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  Meta tag in HTML header

In server response, we can use response.setHeader() to set the meta information in header of a HTML page. The usage is response.setHeader(name,context); meta is used to simulate the response header of HTTP protocol in HTML page. It should be put between the <head> and </head> tag. 1. <meta name="Generator" content="" > <!--This is to specify the tool which generates this page such as Microsoft FrontPage 4.0 etc --> 2. <meta name="keywords" content=""> <!-- To tel...

   HTTP,meta,HTML,head     2013-05-22 11:34:08

  How does MySQL handle DROP TABLE

A few days ago, when executing DROP TABLE in MySQL, all processes including DDL and DML were hung until DROP TABLE was completed. I am confused about this phenomenon. I have reviewed the source codes of MySQL to check how MySQL internally handle DROP TABLE. When user trigger DROP TABLE command: ########################MySQL SERVER drop table######################## /* Sql_table.cc  delete (drop) tables. */bool mysql_rm_table( )   /*   Execute the drop of a normal or temporary...

   MySQL,DROP TABLE     2012-09-24 11:34:05

  Consistency between Redis Cache and SQL Database

Nowadays, Redis has become one of the most popular cache solution in the Internet industry. Although relational database systems (SQL) bring many awesome properties such as ACID, the performance of the database would degrade under high load in order to maintain these properties. In order to fix this problem, many companies & websites have decided to add a cache layer between the application layer (i.e., the backend code which handles the business logic) and the storage layer (i.e., the SQL d...

   REDIS,CACHE,DATABASE     2019-07-07 08:14:16

  strange thing in PHP session variable and local variable

A few minutes ago, I noticed one strange thing when I did my PHP web application development.The situation is described below:I want to display a user's profile using a query parameter user=user_id as the parameter. And also the session variable when user logs in  is $_SESSION["user"].So before displaying the user's profile, I need to either get the query string parameter user and create a local variable called $user and assign value to it as $user=$_REQUEST["user"].Here comes the strange t...

   PHP,session,variable name,change automat     2011-06-13 12:23:59

  Differences among Enter,F5 and Ctrl+F5 in webpage refresh

When we press Enter, F5 or Ctrl+F5 to refresh a webpage, is there any difference among them? Actually it's yes, we can find the difference from the request header and response header information. There are two cases about pressing Enter in the address bar. First if the page requested is cached and not expired in the browser, we can find the header information sent by the browser is : Host 192.168.3.174:8080 User-Agent Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0 Accept ...

   Refresh,F5,Ctrl+F5     2013-06-13 22:03:35

  OpenLDAP Proxy -- Introduction

OpenLDAP is an open source project which is intended to provide some commercial-grade, fully featured applications and development tools based on the well known Light-weight Directory Access Protocol(LDAP). Hence corporations which want to manage their user and group information can freely use these tools.  OpenLDAP provides ldap servers, ldap clients and corresponding tools to work on LDAP. The LDAP server is called slapd(Stand-alone LDAP  daemon). And it would serve as the server whi...

   META,OPENLDAP,OPENLDAP PROXY,SLAPD,SLAPD.CONF,LDAP     2017-10-28 11:20:00

  Fuzzy search algorithm in Sublime Text

Fuzzy string searching is the technique of finding strings that match a pattern approximately (rather than exactly. In many editors, we can easily find the Find menu item to do exact matching. While in Sublime Text and some other editors, we can use fuzzy string searching as well if we just want to have an approximate match. There is some algorithm implemented in Sublime Text to implement achieve this. First the search query is split into characters, join them with a regex wildcard, and then run...

   Sublime Text,Fuzzy search     2013-10-14 22:49:38

  A trap in PDOStatement::bindParam

First, let's check out below codes: <?php $dbh = new PDO('mysql:host=localhost;dbname=test', "test"); $query = <<prepare($query); $bind_params = array(':username' => "laruence", ':password' => "weibo"); foreach( $bind_params as $key => $value ){ $statement->bindParam($key, $value); } $statement->execute(); What is the SQL executed finally? Is there any problem with above codes? Many people may think the query executed is : INSERT INTO `user` (`username`, `password...

   PHP,Trap,bindParam     2013-08-29 10:48:55

  Diving Deeper into HTML5 Offline Browsing

Recently, I published an article on one of the new features in HTML 5 called Offline Browsing  in HTML5 with ApplicationCache.The response to that article was good, and I was asked to expand on some further points including:how to decide on what files to cachethe implications of caching those filesdebugging the ApplicationCacheSo, that’s where this article will start: where the last one finished.  If you haven’t, you should probably read the previous article before this o...

   HTML5,Offline browsing,New breakthrough,Feature     2011-12-20 08:46:06

  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

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