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PHP Development Tips: How to Optimize Database Query Performance
Overview:
In the PHP development process, optimizing database queries is a key part of improving application performance. Effective use of database indexes, reasonable design of database table structures, and use of correct query statements can significantly improve query performance. This article will introduce some common techniques for optimizing database queries based on specific code examples.
ALTER TABLE `user` ADD INDEX `idx_user_id` (`user_id`);
It should be noted that too many indexes will cause performance degradation when inserting, updating, and deleting data. Therefore, when adding indexes, you must weigh the number of indexes and the frequent addition, deletion, and modification operations.
The following are some query optimization code examples:
Query to get the order information of the specified user:
$user_id = 1; $sql = "SELECT order_id, order_name FROM orders WHERE user_id = $user_id"; $result = $conn->query($sql); while ($row = $result->fetch_assoc()) { echo "订单ID:" . $row["order_id"] . ",订单名称:" . $row["order_name"]; }
Use the JOIN statement to query the user's order information:
$user_id = 1; $sql = "SELECT o.order_id, o.order_name FROM orders o JOIN user u ON o.user_id = u.user_id WHERE u.user_id = $user_id"; $result = $conn->query($sql); while ($row = $result->fetch_assoc()) { echo "订单ID:" . $row["order_id"] . ",订单名称:" . $row["order_name"]; }
$user_id = 1; $key = "order_info_" . $user_id; if ($redis->exists($key)) { $order_info = $redis->get($key); } else { $sql = "SELECT order_id, order_name FROM orders WHERE user_id = $user_id"; $result = $conn->query($sql); while ($row = $result->fetch_assoc()) { $order_info[] = $row; } $redis->set($key, serialize($order_info)); $redis->expire($key, 3600); // 缓存过期时间为1小时 } foreach ($order_info as $order) { echo "订单ID:" . $order["order_id"] . ",订单名称:" . $order["order_name"]; }
Summary:
Optimizing database query performance is an essential skill in PHP development. Through appropriate indexes, optimized query statements, reasonable design of database table structures, and caching of query results, application performance can be significantly improved. In actual development, it is necessary to select applicable optimization techniques based on specific scenarios and needs, combined with the characteristics of the database.
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