# 问题 table1 id name description 1 a aaa 2 b bbb 3 c ccc table2 id name description 1 x xxx 2 y yyy 通过 id 更新 table2 的 name 和 description 到 table1 result id name description 1 x xxx 2 y yyy 3 c ccc test data 1234567891011121314151617181920create table table1( id number, name...

# 从关系数据库生成 XML 12345678910111213141516171819202122232425262728293031323334353637383940414243-- create the tablesCREATE TABLE customers ( customer_id INTEGER CONSTRAINT customers_pk PRIMARY KEY, first_name VARCHAR2(10) NOT NULL, last_name VARCHAR2(10) NOT NULL, dob DATE, phone VARCHAR2(12), type...

转载：理解 CSS 中的 BFC (块级可视化上下文) # 开篇 一些元素，如 float 元素，如 position 为 absolute,inline-block,table-cell 或 table-caption 的元素，以及 overflow 属性不为 visible 的元素，它们将会建立一个新的块级格式化上下文。 上述定义已经很详细的描述了块级格式化上下文 (Block Formatting Context) 是如何形成的，为了方便起见，文中均用 BFC 代替。现在，让我们用一种简单的方式对其进行重新定义: BFC 也是 HTML...

# Calculator 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758<!DOCTYPE html><html lang="en"> <head> <meta charset="UTF-8" /> <meta...

# Font # Units 单位 含义 px 一个像素点，1920 x 1080 em 相对父容器的 font-size 的倍数 rem 相对根元素 (html) font-size 的倍数 vw/vh 相对 viewport width/height 的百分比，100vw， 100% 视口宽度 vmin/vmax 相对荧幕较短的一边 / 较长的一边 (一般用于手机横竖屏) em，第一层 div 的 font-size 是 body font-size 的两倍，即 20px，第二层 div font-size 是第一层的两倍，即 40px, 第三层 div font-size...

# XMLHttpRequest The XMLHttpRequest.readyState property returns the state an XMLHttpRequest client is in. An XHR client exists in one of the following states: Value State Description 0 UNSENT Client has been created. open() not called yet. 1 OPENED open() has been...

转载：Forget NodeJS! Build native TypeScript applications with Deno 🦖 | Technorage Have you heard of Deno? If not you should check it out. Deno is a modern JavaScript/TypeScript runtime & scripting environment. Deno is what NodeJS should have been according to Ryan Dahl who created NodeJS....

转载: A Simple Makefile Tutorial Makefiles are a simple way to organize code compilation. This tutorial does not even scratch the surface of what is possible using make, but is intended as a starters guide so that you can quickly and easily create your own makefiles for small to medium-sized...

转载: The C compilation process - Codeforwin In the series of C tutorial we learned some basic of C programming language, configured C compiler and learned to compile and execute C program. Since the compilation and execution of first C program, I must answer few questions before moving ahead....

转载：Build a Web Crawler in Go One of the basic tests I use to try out a new programming language is building a web crawler. I stole the idea from my colleague Mike Lewis and I love it because it uses all the principles necessary in internet engineering: A web crawler needs to parse semi-structured...