手写php7.0到php8.0可以使用mysql数据库增删改查一个类库

class Database {
    
    private $host;
    private $user;
    private $pass;
    private $dbname;
    private $charset;
    private $pdo;

    public function __construct($host, $user, $pass, $dbname, $charset='utf8mb4') {
        $this->host = $host;
        $this->user = $user;
        $this->pass = $pass;
        $this->dbname = $dbname;
        $this->charset = $charset;
        $this->connect();
    }

    private function connect() {
        $dsn = "mysql:host={$this->host};dbname={$this->dbname};charset={$this->charset}";
        $this->pdo = new PDO($dsn, $this->user, $this->pass);
        $this->pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        $this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    }

    public function query($sql, $params = []) {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        return $stmt;
    }

    public function fetchAll($sql, $params = []) {
        $stmt = $this->query($sql, $params);
        return $stmt->fetchAll();
    }

    public function fetch($sql, $params = []) {
        $stmt = $this->query($sql, $params);
        return $stmt->fetch();
    }

    public function insert($table, $data) {
        $keys = array_keys($data);
        $fields = implode(",", $keys);
        $values = ":" . implode(",:", $keys);
        $sql = "INSERT INTO $table ($fields) VALUES ($values)";
        $this->query($sql, $data);
        return $this->pdo->lastInsertId();
    }

    public function update($table, $data, $where) {
        $set = [];
        foreach($data as $key => $value) {
            $set[] = "$key = :$key";
        }
        $set = implode(",", $set);
        $sql = "UPDATE $table SET $set WHERE $where";
        return $this->query($sql, $data);
    }

    public function delete($table, $where) {
        $sql = "DELETE FROM $table WHERE $where";
        return $this->query($sql);
    }
}

可以使用PHP Data Object (PDO)来连接和操作MySQL数据库。以下是一个基本的类库，可用于执行增删改查操作。

$db = new Database('localhost', 'username', 'password', 'database');
$rows = $db->fetchAll("SELECT * FROM users");
foreach ($rows as $row) {
    echo $row['name'];
}

此类库使用PDO来连接和操作MySQL数据库，因此您需要启用PDO扩展模块以使用此库。

下面是基于 mysqli 扩展实现的简单数据库类库，可以进行增删改查操作

class MySQLiDB {
    private $host;
    private $user;
    private $password;
    private $dbname;
    private $charset;
    private $conn;

    // 构造函数
    public function __construct($host, $user, $password, $dbname, $charset = 'utf8') {
        $this->host = $host;
        $this->user = $user;
        $this->password = $password;
        $this->dbname = $dbname;
        $this->charset = $charset;

        // 连接数据库
        $this->conn = mysqli_connect($this->host, $this->user, $this->password, $this->dbname);
        if (!$this->conn) {
            die('连接失败：' . mysqli_connect_error());
        }

        // 设置字符集
        mysqli_set_charset($this->conn, $this->charset);
    }

    // 执行 SQL 语句
    private function query($sql) {
        $result = mysqli_query($this->conn, $sql);
        if (!$result) {
            die('执行 SQL 语句失败：' . mysqli_error($this->conn));
        }
        return $result;
    }

    // 查询多行数据
    public function select($sql) {
        $result = $this->query($sql);
        $rows = array();
        while ($row = mysqli_fetch_assoc($result)) {
            $rows[] = $row;
        }
        return $rows;
    }

    // 查询一行数据
    public function find($sql) {
        $result = $this->query($sql);
        $row = mysqli_fetch_assoc($result);
        return $row;
    }

    // 插入数据
    public function insert($table, $data) {
        $keys = array();
        $values = array();
        foreach ($data as $key => $value) {
            $keys[] = "`" . mysqli_real_escape_string($this->conn, $key) . "`";
            $values[] = "'" . mysqli_real_escape_string($this->conn, $value) . "'";
        }
        $key_str = implode(',', $keys);
        $value_str = implode(',', $values);
        $sql = "INSERT INTO `$table` ($key_str) VALUES ($value_str)";
        $this->query($sql);
        return mysqli_insert_id($this->conn);
    }

    // 更新数据
    public function update($table, $data, $condition) {
        $set = array();
        foreach ($data as $key => $value) {
            $set[] = "`" . mysqli_real_escape_string($this->conn, $key) . "`='" . mysqli_real_escape_string($this->conn, $value) . "'";
        }
        $set_str = implode(',', $set);
        $sql = "UPDATE `$table` SET $set_str WHERE $condition";
        $this->query($sql);
        return mysqli_affected_rows($this->conn);
    }

    // 删除数据
    public function delete($table, $condition) {
        $sql = "DELETE FROM `$table` WHERE $condition";
        $this->query($sql);
        return mysqli_affected_rows($this->conn);
    }

    // 析构函数
    public function __destruct() {
        mysqli_close($this->conn);
    }
}

使用方法如下：

//实例化类并连接数据库
$db = new MySQLiDB('localhost', 'username', 'password', 'database_name');
//查询多行数据
$sql = "SELECT * FROM `table_name` WHERE `id` > 1";
$result = $db->select($sql);
//查询一行数据
$sql = "SELECT * FROM `table_name` WHERE `id` = 1";
$result = $db->find($sql);
//插入数据
$data = array(
    'name' => 'blackcatw',
    'age' => 25,
    'email' => '[email protected]'
);
$table = 'table_name';
$db->insert($table, $data);
//更新数据
$data = array(
    'name' => 'John Doe',
    'age' => 30
);
$condition = "`id` = 1";
$table = 'table_name';
$db->update($table, $data, $condition);
//删除数据
$condition = "`id` = 1";
$table = 'table_name';
$db->delete($table, $condition);

注意：在执行 SQL 语句时，应该确保 SQL 语句中的变量已经进行了安全转义，以避免 SQL 注入攻击。这里的类库使用了 mysqli_real_escape_string 函数来进行安全转义。