SEARCH KEYWORD -- DATABASE


  Why cannot compare double values directly for equality?

A question in PHP: Get some value from the database and use floatval() to convert it to floatint point value, then compare it with another value which is also converted to floating point value with floatval(). These two values are the same when using var_dump() to output, the two outputs are float(8.87), they are the same. But when comparing them for equality, the result is weird., they are not equal. Why?To analyze this question, we need to start with PHP data types. PHP uses weak types. In PHP...

   PHP,floating, precision,compare,equality     2012-06-27 09:01:36

  Why is single threaded Redis so fast

Redis is a high-performance, in-memory key-value database. According to official test reports, it can support around 100,000 QPS (queries per second) on a single machine. However, Redis uses a single-threaded architecture in its design. Why does Redis still have such high performance with a single-threaded design? Wouldn't it be better to use multiple threads for concurrent request processing? In this article, let's explore why Redis has a single-threaded architecture and still maintains its spe...

   REDIS,SINGLE-THREADED,MULTI-THREADING     2023-02-28 05:16:22

  Use of Erlang in WhatsApp

After many years, people are still discussing whether Erlang is a small language. People have all sorts of doubt about it, but with the appearance of WhatsApp, we may change our mind. What is WhatsApp, from its official website: WhatsApp Messenger is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. The more funny thing is the main developer of WhatsApp Rick Reed worked in Yahoo and SGI before he joined WhatsApp and he didn't have any know...

   Erlang,WhatsApp,Architecture     2013-06-16 03:03:46

  All I Know About Certificates -- Websites

In last article, we know the role of clients and their responsibilities for certificate verification. Finally, let's talk about websites. We've discussed many potential issues between CAs and clients concerning certificates, but the most frequent issue is with websites—many websites have faced this problem: certificate expiration. Websites need to ensure two things: Ensure their certificate does not expire. Protect their private key from being leaked. If someone else obtains the priv...

   CLIENTS,WEBSITES,SSL CERTIFICATE,CERTIFICATE AUTHORITY,CA     2024-07-26 22:33:29

  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

  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

  PHP Apache MySQL Set-up Note

With the emergence of WAMP, LAMP, PHP developers are liberated from the tedious work of setting up PHP environment. Since PHP, Apache and MySQL are so tightly bundled, WAMP and LAMP provide a setp solution for setting up a PHP environment which includes the programming programming environment, server and database. But for a PHP who wants to learn more, you have to try to set the PHP environment yourself by installing PHP, Apache and MySQL manually and configuring them. Below is a simple note on ...

   PHP,Apache,MySQL     2014-04-07 01:56:43

  â€œExperience says it all”- Pentaho ETL Developers’ Comment on the Use of ETL Tools

Since months Pentaho ETL developers have been juggling with three distinct tools- Pentaho DI, SSIS, and PowerShell. Their experience has provided them new perspective on the cons and pros of every tool. In this post, they are sharing their experience with these tools and explain their significance. Before getting started, they first would like to explain ETL in brief and how the tools suits ETL landscape. ETL is Extract Transform Load. Informatica was the initial ETL tool introduced in the mid n...

   Pentaho BI ETL tools     2015-05-13 01:14:57

  Which Type of IT Career is Best For You?

Considering the growth of the information technology job market, a career in IT is an incredibly smart career move.  A career in IT can mean many things – you can become a network administration, website developer, database specialist, programmer or engineer. The job range is vast and can suit various personalities and levels of technical skill. Having a good insight into those job profiles is key to make the right decision about your career path. Here's a selection of some of the mos...

   career,IT,tips     2014-07-30 09:21:40

  Simple PHP paging class

Frequently in our web applications, we may have many records in the database to display. In order to imrpove loading speed and efficiency, we may need to display some records at a time, so we need to paginate the records. For example, if we have 1 million book records and when users want to view the book list, it's inefficient to display all the records on the same page, we may need to have some pagination to allow displaying a portion of the records such as 20 records per page. This is a simple...

   PHP,Paging,Class     2012-09-10 20:23:33

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