How to connect to SQLite database using PDO

How to connect to a SQLite database using PDO

When developing web applications, the database is an indispensable technology. SQLite is a lightweight embedded database engine that is widely used in a variety of applications. This article will introduce how to use PHP's PDO (PHP Data Object) extension to connect to a SQLite database and provide some code examples.

PDO is a unified interface for PHP used to access different databases. Using PDO makes it easy to switch between different databases without modifying too much code. SQLite is one of the databases supported by PDO, let's see how to connect to a SQLite database using PDO.

First, we need to ensure that the SQLite database has been installed on the server and the PDO extension has been enabled. If it is not installed, please install and configure it according to your own server environment.

Next, we need to create a SQLite database file that will store our data. We can use SQLite's command line tools or other SQLite management tools to create an empty database.

Now, we can start writing PHP code to connect to the SQLite database. Here is a simple example:

<?php
try {
    // 连接到SQLite数据库
    $pdo = new PDO("sqlite:/path/to/database.db");
    
    // 设置错误报告模式为异常模式
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    
    // 执行查询语句
    $statement = $pdo->query("SELECT * FROM users");
    
    // 遍历结果集
    while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
        echo "ID: " . $row['id'] . ", Name: " . $row['name'] . "<br>";
    }
} catch(PDOException $e) {
    // 处理异常
    echo "连接到数据库时发生错误： " . $e->getMessage();
}

In the above example, we first create a PDO object using the new PDO() function and pass it the path to the SQLite database file as a parameter . Next, we set the first parameter of the setAttribute() method to PDO::ATTR_ERRMODE and the second parameter to PDO::ERRMODE_EXCEPTION to throw an exception when an error occurs.

Then, we use the query() method to execute a simple query statement and assign the result to a variable. Finally, we use the fetch() method to traverse the result set and print out the data for each row.

It should be noted that the path /path/to/database.db in the above example should be replaced with the actual database file path.

In addition to executing query statements, we can also use PDO objects to perform other database operations, such as inserting, updating, and deleting data. The following is a sample code:

<?php
try {
    // 连接到SQLite数据库
    $pdo = new PDO("sqlite:/path/to/database.db");
    
    // 设置错误报告模式为异常模式
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    
    // 插入数据
    $pdo->exec("INSERT INTO users (name) VALUES ('John')");
    
    // 更新数据
    $pdo->exec("UPDATE users SET name = 'Jane' WHERE id = 1");
    
    // 删除数据
    $pdo->exec("DELETE FROM users WHERE id = 1");
} catch(PDOException $e) {
    // 处理异常
    echo "连接到数据库时发生错误： " . $e->getMessage();
}

In the above example, we used the exec() method to execute INSERT, UPDATE and DELETE statements to insert, update and delete data.

Summary
This article explains how to use PDO to connect to a SQLite database and provides some code examples. Connecting to a SQLite database using PDO is very simple, requiring only a few lines of code to complete the connection and database operations. Using PDO to connect to a SQLite database is a common way to develop web applications, which can greatly improve development efficiency. Hope this article can be helpful to you!

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