我怎样治愈梨状肌综合症（经验分享）

努力

我們用力分手；
我們無力挽回。

努力

我們用力的去分開；
我們沒力的去挽留。

未來

next - receipt

next - receipt

future page

Using PHP to Backup MySQL Databases

http://www.php-mysql-tutorial.com/wikis/mysql-tutorials/using-php-to-backup-mysql-databases.aspx

There are at least three ways to backup your MySQL Database :

1. Execute a database backup query from PHP file.
2. Run mysqldump using system() function.
3. Use phpMyAdmin to do the backup.

Execute a database backup query from PHP file Below is an example of using SELECT INTO OUTFILE query for creating table backup : <?php include 'config.php'; include 'opendb.php'; $tableName  = 'mypet'; $backupFile = 'backup/mypet.sql'; $query      = "SELECT * INTO OUTFILE '$backupFile' FROM $tableName"; $result = mysql_query($query); include 'closedb.php'; ?> To restore the backup you just need to run LOAD DATA INFILE query like this : <?php include 'config.php'; include 'opendb.php'; $tableName  = 'mypet'; $backupFile = 'mypet.sql'; $query      = "LOAD DATA INFILE 'backupFile' INTO TABLE $tableName"; $result = mysql_query($query); include 'closedb.php'; ?> It's a good idea to name the backup file as tablename.sql so you'll know from which table the backup file is

Run mysqldump using system() function The system() function is used to execute an external program. Because MySQL already have built in tool for creating MySQL database backup (mysqldump) let's use it from our PHP script <?php include 'config.php'; include 'opendb.php'; $backupFile = $dbname . date("Y-m-d-H-i-s") . '.gz'; $command = "mysqldump --opt -h $dbhost -u $dbuser -p $dbpass $dbname | gzip > $backupFile"; system($command); include 'closedb.php'; ?>

Use phpMyAdmin to do the backup

This option as you may guessed doesn't involve any programming on your part. However I think i mention it anyway so you know more options to backup your database.
To backup your MySQL database using phpMyAdmin click on the "export" link on phpMyAdmin main page. Choose the database you wish to backup, check the appropriate SQL options and enter the name for the backup file.

<style type="text/css"> .style1 { width: 615px; } .style2 { text-align: right; width: 85px; } </style>

MySQL的JOIN用法

https://www.jianshu.com/p/600b99a8bc7f

数据库中的JOIN称为连接，连接的主要作用是根据两个或多个表中的列之间的关系，获取存在于不同表中的数据。连接分为三类：内连接、外连接、全连接。另外还有CROSS JOIN(笛卡尔积)，个人认为如果要理解MySQL中JOIN的各种连接，只需要理解笛卡尔积就足够了。

1 笛卡尔积

笛卡尔乘积是指在数学中，两个集合X和Y的笛卡尓积（Cartesian product），又称直积，表示为X × Y，第一个对象是X的成员而第二个对象是Y的所有可能有序对的其中一个成员。

下面一张图很好解释了笛卡尔积：

 

 

2 数据准备

• 创建两张表：t1和t2

 

 

表t1和t2中的数据如下：

 

3 CROSS JOIN

笛卡尔积就是将表1的每条记录与表2中的每一条记录拼成数据对，CROSS JOIN的SQL执行语句如下：

执行结果如下：

 

 

MySQL tutorial 15 - joining 2 tables

Display a clock - Tryit Editor v3.6 (JavaScript)

<!DOCTYPE html>
<html>
<head>
<script>
function startTime() {
  var today = new Date();
  var h = today.getHours();
  var m = today.getMinutes();
  var s = today.getSeconds();
  m = checkTime(m);
  s = checkTime(s);
  document.getElementById('txt').innerHTML =
  h + ":" + m + ":" + s;
  var t = setTimeout(startTime, 500);
}
function checkTime(i) {
  if (i < 10) {i = "0" + i};  // add zero in front of numbers < 10
  return i;
}
</script>
</head>

<body onload="startTime()">

<div id="txt"></div>

</body>
</html>

JavaScript Array push() Method

Add a new item to an array:

var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.push("Kiwi");  
 

https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_push

<!DOCTYPE html>
<html>
<body>

<p>Click the button to add a new element to the array.</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits;

function myFunction() {
  fruits.push("Kiwi");
  document.getElementById("demo").innerHTML = fruits;
}
</script>

</body>
</html>