Resource recommendations for MySQLi extension library video tutorials

Introduction: "MySQLi Extension Library Video Tutorial" explains the specific use and precautions of MySQLi from both object-oriented and process-oriented aspects. Finally, it provides a detailed analysis of how to use MySQLi in actual development through a practical drill of the no-refresh comment system. Complete the operation on the database.

Course playback address: http://www.php.cn/course/396.html

The teacher’s teaching style:

The teacher’s lectures are simple, clear, layer-by-layer analysis, interlocking, rigorous argumentation, rigorous structure, and use the logical power of thinking to attract students’ attention Strength, use reason to control the classroom teaching process. By listening to the teacher's lectures, students not only learn knowledge, but also receive thinking training, and are also influenced and infected by the teacher's rigorous academic attitude

The more difficult point in this video is MySQLi-based object-oriented programming (1):

As part of the PHP extension library, mysqli is a good interface for operating databases. There are two ways to operate mysqli, one is process-oriented and the other is object-oriented. This article mainly talks about the object-oriented mysqli operation, mainly as an introduction. For more information, I hope you can refer to the official PHP documentation. After reading this article, please refer to the documentation. I believe that the operation of mysqli will be easy to get started

Mysqli's basic operation process:

<?php
// 连接数据库
$mysqli = new mysqli(&#39;localhost&#39;, &#39;root&#39;, &#39;&#39;); 

/*
选择数据库,也可以在mysqli的构造函数的第四个参数处给出
*/
$mysqli->select_db(&#39;mydb&#39;); 

//设置字符集
$mysqli->set_charset(&#39;utf8&#39;);
//执行操作
$mysqli->query(&#39;SELECT * FROM users&#39;);
$result = $mysqli->fetch_all();
//关闭连接
$mysqli->close();

Here, use new to create a new mysqli object, and pass in the relevant parameters of the database connection to obtain a mysqli object. You can use $mysqli->connect_errno to determine whether the connection is incorrect. The specific error information can be obtained through $mysqli->connet_error.

After connecting to the database, you must first select the database. Here, $mysqli->select-db('mydb') is used. Then you can set the character set.
After selecting the database, you can operate the database. You can use the query method of the mysqli object to execute MySQL statements. What needs to be noted here is:

For general sql statements: SELECT/DESC/DESCRIBE/SHOW/EXPLAN returns the mysqli_result object if the execution is successful, and returns false if the execution fails. For the execution of other SQL statements, true is returned if the execution is successful, otherwise false is returned. (Excluding prepared statements)

So regular insert / delete / update, etc. will return true or false to indicate whether the sql statement is successfully executed.
After executing the sql statement, you can use the insert_id attribute of the mysqli object to view the value of the self-increasing field of the data just inserted into the table. Use the affected_rows attribute to view the number of affected data rows, and the error and errno attributes to view error information

$mysqli->query("INSERT INTO users(name, pass) VALUES ('good' , 'nice')");
echo $mysqli->insert_id;
// 插入数据的自增长数据的值
echo $mysqli->affected_rows; 
// 影响的记录条数

The select statement executed through the query method will return a mysqli_result object, which is the result set object of the query. You can use $mysqli_result ->fetch_all() and other methods to obtain the query results.

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