SEARCH KEYWORD -- timestamp


  Convert time to Unix time

Unix time is defined as the number of seconds that have elapsed since midnight Coordinated Universal Time (UTC), 1 January 1970,not counting leap seconds. It is used widely in Unix-like and many other operating systems and file formats. It is neither a linear representation of time nor a true representation of UTC. Unix time may be checked on some Unix systems by typing date +%s on the command line. Sometimes it's a bit difficult to compare times stored in different applications or systems with ...

   UNIX time, Oracle DATE, conversion, timestamp     2013-01-19 09:04:17

  CASSANDRA data model

Cassandra is an open source distributed database, it combines dynamic key/value and column oriented feature of Bigtable. Features of Cassandra are: Flexible schema, no need to design schema first, it's very convenient to add or delete strings Support range search on keys High usability, extensible. The single node error will not affect the cluster. We can think Cassandra's data model as a 4 or 5 dimensional Hash. COLUMN Columns is the smallest data unit in Cassandra, it is a 3 dimensional data...

   Cassandra,database,sort     2013-06-08 22:07:40

  Date interval add and sub prior to PHP 5.3

After PHP 5.3, we can use DateInterval object or date_interval_create_from_date_string() function to add or subtract days,weeks,months or years to or from a DateObject.But prior to PHP 5.3,we cannot do this. If we want to achieve the same effect. We need to use some skills. Here is one:We can use strtotime() function to achieve this. For example:$date=date('Y-m-d',time());$datestamp=strtotime(date('Y-m-d',strtotime($date)).' +1 day'); $datestamp=strtotime(date('Y-m-d',strtotime($date)).' +1...

   PHP,DateInterval,Class,PHP 5.3,PHP 5.2     2011-10-21 10:50:10

  Remote form submission

Remote form submission is way of submitting HTML forms from local to a particular remote server. This is used by many advertisers, spammers or even hackers to submit bad data to other websites in order to get what they want. They can write some automation scripts to help them do spamming. How can people do remote form submission and how to prevent this kind of attacks? Since a website can be accessed by almost every one, so one can save a local copy of a HTML form of a website through File->S...

   PHP,Security,Remote form submission     2013-07-14 01:04:49

  Guide on recovering data in MySQL

In our daily work, there might be mistakes made which got some data or even databases deleted in MySQL. If this happens on production, it would be a nightmare. In case this happens, normally DBA would jump in to save the world. And they would try to recover the data from the backup if there is any. But if there is no backup, then the show stops. Hence database backup is necessary on production environments to avoid such awkward situation. Also normally in MySQL, binlog should be enabled as well ...

   MYSQL,DATABASE,BACKUP,BINLOG,EXAMPLE     2020-08-26 07:50:30

  Data type in MySQL

For both small free database space and large e-commerce websites, reasonable database table structure design is essential. To achieve this, it requires us to have a full understanding of commonly used data types in database system. Below we share some knowledge about data types in MySQL.1. Numeric typesThe numeric types can be classified as : integer, float and decimal type.The so-called "decimal" refers DECIMAL and NUMERIC, they are of the same type. Strictly speaking it is not a numeric type, ...

   MySQL, Data type,VARCHAR     2013-01-01 10:56:06

  Understand diff in Unix

diff is an important tool program in Unix. It is used to compare differences of two files, it is the foundation for code version control. If you type : $ diff <file_before_change> <file_after_change> diff will tell you what's the difference between these two files. The result may not be so easy to understand, so now I will show you how to understand diff. 1. 3 formats of diff diff has 3 formats due to historic reasons. normal diff context diff unified diff 2. Demo files For easy d...

   diff,Unix,version control,git     2012-09-03 10:49:36

  How to check why Vim is slow

On *nix, some processes may not be able to start up, software runs very slowly suddenly and software's "Segment Fault" are some issues faced by many *nix users. Here we show you how to use truss to trace why Vim becomes slow suddenly. Operating system : FreeBSD-5.2.1-releas vim version is 6.2.154, after typing vim on command line, sometimes we need to wait for a few minutes to get into the edit interface and there is no error output. After carefully checking .vimrc and all vim settings, there ar...

   vim, truss, linux     2012-11-26 11:54:35

  Let's talk about JavaScript deep clone

In JavaScript, deep clone means creating a brand new object that includes all nested objects, with all properties being completely independent copies. This is different from shallow copying, which only copies the first-level properties, with nested objects being referenced rather than copied. There are multiple ways to perform deep copying in JavaScript, but the best one to use depends on the specific use case. Can use JSON.parse & JSON.stringify? ❌ JSON.parse(JSON.stringify(obj)) is a dep...

   JAVASCRIPT,DEEP CLONE     2023-02-25 08:57:11

  Something you may not know about Shell

Shell is also called command line interface, it is the interface between *nix users and computer. Shell is a program which provides service to access OS kernel services. This article is to introduce some not so well known but useful and interesting knowledge about shell. Wiki shell was born almost at the same time as Unix. The first UNIX shell was written by Ken Thompson in 1971 and its name is Thompson sh. It's older than Linux kernel. The default Shell in most *nix and MacOS is bash, bash was...

   Linux, Unix,Shell,Command     2012-11-24 07:19:47

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