Backend Development
PHP Tutorial
Please help me see if there is anything wrong with this database connection code?
Please help me see if there is anything wrong with this database connection code?
I am a novice learning PHP. There are no good examples in books, and there are also mistakes on the Internet. I wrote a complete one according to the PHP manual
Experts can help me take a look and see if there are any mistakes...Thank you
<code>//面向对象
$mysqli = new mysqli("localhost", "user", "pass", "database");
if(mysqli_connect_errno())) { //这边判断方式和下面面向过程中的直接判断变量有什么区别？
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT `name`, `address`, `phone` FROM Users WHERE gender=? AND age=?";
if($stmt = $mysqli->prepare($query) {
$stmt->bind_param("si", $gender, $age); //这边插入参数是不是写在这里？
$stmt->execute();
$stmt->bind_result($name, $address, $phone);
while($stmt->fetch()) {
printf ("%s (%s,%s)<br />", $name, $address, $phone);
}
$stmt->close();
}
$mysqli->close();
/面向过程
$mysqli = mysqli_connecti("localhost", "user", "pass", "database");
if(!$mysqli) {
printf ("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT `name`, `address`, `phone` FROM Users WHERE gender=? AND age=?";
if ($stmt = mysqli_prepare($query)){
mysqli_stmt_bind_param($stmt, "si", $gender, $age);
mysqli_stmt_execute($stmt);
mysqli_stmt_bind_result($stmt, $name, $address, $phone);
while (mysqli_stmt_fetch($stmt)) {
printf ("%s (%s,%s)<br />", $name, $address, $phone);
}
mysqli_stmt_close($stmt);
}
$mysqli_close();</code>Reply content:
I am a novice learning PHP. There are no good examples in books, and there are also mistakes on the Internet. I wrote a complete one according to the PHP manual
Experts can help me take a look and see if there are any mistakes...Thank you
<code>//面向对象
$mysqli = new mysqli("localhost", "user", "pass", "database");
if(mysqli_connect_errno())) { //这边判断方式和下面面向过程中的直接判断变量有什么区别？
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT `name`, `address`, `phone` FROM Users WHERE gender=? AND age=?";
if($stmt = $mysqli->prepare($query) {
$stmt->bind_param("si", $gender, $age); //这边插入参数是不是写在这里？
$stmt->execute();
$stmt->bind_result($name, $address, $phone);
while($stmt->fetch()) {
printf ("%s (%s,%s)<br />", $name, $address, $phone);
}
$stmt->close();
}
$mysqli->close();
/面向过程
$mysqli = mysqli_connecti("localhost", "user", "pass", "database");
if(!$mysqli) {
printf ("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT `name`, `address`, `phone` FROM Users WHERE gender=? AND age=?";
if ($stmt = mysqli_prepare($query)){
mysqli_stmt_bind_param($stmt, "si", $gender, $age);
mysqli_stmt_execute($stmt);
mysqli_stmt_bind_result($stmt, $name, $address, $phone);
while (mysqli_stmt_fetch($stmt)) {
printf ("%s (%s,%s)<br />", $name, $address, $phone);
}
mysqli_stmt_close($stmt);
}
$mysqli_close();</code>
Code is written and run. Whether the code is written correctly or not, you have to ask the compiler or parser, they are the real teachers.
Run it yourself. . .
This doesn’t look good to the naked eye. There seems to be something wrong with the last sentence. You have to pass in the parameter ($mysqli).
bind_result+loop fetch after prepare+execute is the traditional approach.
Starting from PHP 5.4, the bottom layer uses mysqlnd by default to implement mysql, mysqli, pdo_mysql.
At this time, you can use get_result and fetch_all to quickly get the query results.
After prepare+execute $stmt->get_result()->fetch_all(MYSQLI_ASSOC) You can get the result set.
For example:
<code>post.php?id=1024
MySQLi普通查询:
$db = new mysqli('127.0.0.1','user','pass','dbname',3306);
var_export($db->query('SELECT * FROM posts WHERE id='.intval($_GET['id']))->fetch_all());
MySQLi预处理绑定参数查询:
$db = new mysqli('127.0.0.1','user','pass','dbname',3306);
$stmt = $db->prepare('SELECT * FROM posts WHERE id=?'); //预处理
$stmt->bind_param('i', $_GET['id']); //绑定参数(可以防止SQL注入)
$stmt->execute(); //查询
var_export($stmt->get_result()->fetch_all());</code>
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
MySQL: Simple Concepts for Easy Learning
Apr 10, 2025 am 09:29 AM
MySQL is an open source relational database management system. 1) Create database and tables: Use the CREATEDATABASE and CREATETABLE commands. 2) Basic operations: INSERT, UPDATE, DELETE and SELECT. 3) Advanced operations: JOIN, subquery and transaction processing. 4) Debugging skills: Check syntax, data type and permissions. 5) Optimization suggestions: Use indexes, avoid SELECT* and use transactions.
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
What is Cross-Site Request Forgery (CSRF) and how do you implement CSRF protection in PHP?
Apr 07, 2025 am 12:02 AM
In PHP, you can effectively prevent CSRF attacks by using unpredictable tokens. Specific methods include: 1. Generate and embed CSRF tokens in the form; 2. Verify the validity of the token when processing the request.
PHP's Purpose: Building Dynamic Websites
Apr 15, 2025 am 12:18 AM
PHP is used to build dynamic websites, and its core functions include: 1. Generate dynamic content and generate web pages in real time by connecting with the database; 2. Process user interaction and form submissions, verify inputs and respond to operations; 3. Manage sessions and user authentication to provide a personalized experience; 4. Optimize performance and follow best practices to improve website efficiency and security.
PHP vs. Python: Understanding the Differences
Apr 11, 2025 am 12:15 AM
PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.
The Future of PHP: Adaptations and Innovations
Apr 11, 2025 am 12:01 AM
The future of PHP will be achieved by adapting to new technology trends and introducing innovative features: 1) Adapting to cloud computing, containerization and microservice architectures, supporting Docker and Kubernetes; 2) introducing JIT compilers and enumeration types to improve performance and data processing efficiency; 3) Continuously optimize performance and promote best practices.
