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Discussion on the underlying development principles of PHP: database connection and query optimization technology
Introduction:
PHP is an advanced scripting language that is widely used in the field of Web development . In the underlying development of PHP, database connection and query optimization are important and common tasks. This article will discuss two aspects: database connection and query optimization, and provide code examples with examples to help readers better understand and apply these technologies.
1. Database connection technology
The following is a simple sample code showing how to use PDO for database connection:
$dsn = 'mysql:host=localhost;dbname=test'; $user = 'root'; $pass = 'password'; try { $pdo = new PDO($dsn, $user, $pass); echo '数据库连接成功!'; } catch(PDOException $e) { echo '数据库连接失败:' . $e->getMessage(); }
The following is a simple sample code showing how to use MySQLi for database connection:
$mysqli = new mysqli("localhost", "root", "password", "test"); if ($mysqli->connect_errno) { echo '数据库连接失败:' . $mysqli->connect_error; } else { echo '数据库连接成功!'; }
2. Query optimization technology
The following is a sample code that demonstrates how to create an index in MySQL:
CREATE INDEX idx_name ON users (name);
The following is a simple sample code showing how to use prepared statements to perform database queries:
$stmt = $pdo->prepare('SELECT * FROM users WHERE id = :id'); $stmt->bindParam(':id', $id, PDO::PARAM_INT); $stmt->execute(); $result = $stmt->fetchAll(PDO::FETCH_ASSOC);
The following is a sample code that demonstrates how to query only the required fields:
$stmt = $pdo->prepare('SELECT name, email FROM users'); $stmt->execute(); $result = $stmt->fetchAll(PDO::FETCH_ASSOC);
Conclusion:
This article mainly introduces the technology of database connection and query optimization in the underlying development of PHP . By rationally selecting and using database connection methods, using indexes, preprocessing statements, and avoiding unnecessary queries, database performance and query efficiency can be effectively improved. Developers can flexibly apply these technologies according to actual project needs, thereby improving the overall performance of the application.
References:
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