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一个故事告诉你比特币的原理及运作机制 - 创意 - 清泛网 - 专注C/C++及内核技术
...这样以物易物实在太不方便了，于是村子全员开会，讨论如何解决这个问题。有人提议，以便于分割且稀有的东西，例如黄金，作为一般等价物，把其它物品和黄金的对应关系编成一张表格，例如一克黄金对应一只羊，一克黄金...
How is Docker different from a virtual machine?
...e host, see superuser.com/questions/889472/…. However, to illustrate the union filesystem of the containers, there could be a shared layer of libs/bins directly above the docker engine.
– Betamos
Dec 5 '15 at 1:33
...
How can I get the SQL of a PreparedStatement?
...
This also depends on the implementation. In MySQL -- at least the version I was using a few years ago -- the JDBC driver actually built a conventional SQL query from the template and bind variables. I guess that version of MySQL didn't support prepared statements nativ...
SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column
... Having a problem with a similar situation in PhpMyAdmin over MySQL. In my case, the source and destination columns are in the same table, but record selection is based on the other table. The "SELECT" version of the query works, but the UPDTATE statement throws a syntax error at "FRO...
mysql实现split分割字符串（length, SUBSTRING_INDEX, substring） - 爬虫/...
由于MySql没有直接的split函数，只提供了length, SUBSTRING_INDEX, substring三个函数，这里介绍如何用这三个函数实现split功能。
# SUBSTRING_INDEX(str, delim, count)：返回字符串 str 中在第 count 个出现的分隔符 delim 之前的子串。如果 count 是...
Mysql substr和Oracle substr区别 - 爬虫/数据库 - 清泛IT社区，为创新赋能！
Oracle substr(字符串，开始索引、从0起，长度)
Mysql substr或substring(字符串，开始索引、从1起，长度)
Can you get DB username, pw, database name in Rails?
...%
require 'parseconfig'
c=ParseConfig.new('../../.my.cnf') %>
mysqlevn: &mysql
adapter: mysql
username: <%= c.params['client']['user'] %>
password: <%= c.params['client']['password'] %>
host: localhost
socket: <%= [
'/var/run/mysqld/mysqld.sock',
'/va...
Upgrading PHP in XAMPP for Windows?
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Take a backup of your htdocs and data folder (subfolder of MySQL folder), reinstall upgraded version and replace those folders.
Note:
In case you have changed config files like PHP (php.ini), Apache (httpd.conf) or any other, please take back up of those files as well and replace th...
Get environment variable value in Dockerfile
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add -e key for passing environment variables to container.
example:
$ MYSQLHOSTIP=$(sudo docker inspect -format="{{ .NetworkSettings.IPAddress }}" $MYSQL_CONRAINER_ID)
$ sudo docker run -e DBIP=$MYSQLHOSTIP -i -t myimage /bin/bash
root@87f235949a13:/# echo $DBIP
172.17.0.2
...
新手程序员应该知道的7件事 - 创意 - 清泛网 - 专注C/C++及内核技术
...。掌握类似于find、comm、diff、vi/vim、sed、awk等工具。知道如何用命令行来查找文件等等，都可以在你写脚本的时候为你减负。”
Bull，是一位先用微软工具，然后逐渐转移到Linux的程序员，对此表示赞同：“了解命令行的来龙去...