PHP基于MySQLI函数封装的数据库连接工具类【定义与用法】

<?phpclass mysql{  private $mysqli;  private $result;  /**   * 数据库连接   * @param $config 配置数组   */  public function connect($config)  {    $host = $config['host'];    //主机地址    $username = $config['username'];//用户名    $password = $config['password'];//密码    $database = $config['database'];//数据库    $port = $config['port'];    //端口号    $this->mysqli = new mysqli($host, $username, $password, $database, $port);  }  /**   * 数据查询   * @param $table 数据表   * @param null $field 字段   * @param null $where 条件   * @return mixed 查询结果数目   */  public function select($table, $field = null, $where = null)  {    $sql = "SELECT * FROM {$table}";    if (!empty($field)) {      $field = '`' . implode('`,`', $field) . '`';      $sql = str_replace('*', $field, $sql);    }    if (!empty($where)) {      $sql = $sql . ' WHERE ' . $where;    }    $this->result = $this->mysqli->query($sql);    return $this->result->num_rows;  }  /**   * @return mixed 获取全部结果   */  public function fetchAll()  {    return $this->result->fetch_all(MYSQLI_ASSOC);  }  /**   * 插入数据   * @param $table 数据表   * @param $data 数据数组   * @return mixed 插入ID   */  public function insert($table, $data)  {    foreach ($data as $key => $value) {      $data[$key] = $this->mysqli->real_escape_string($value);    }    $keys = '`' . implode('`,`', array_keys($data)) . '`';    $values = '/'' . implode("','", array_values($data)) . '/'';    $sql = "INSERT INTO {$table}( {$keys} )VALUES( {$values} )";    $this->mysqli->query($sql);    return $this->mysqli->insert_id;  }  /**   * 更新数据   * @param $table 数据表   * @param $data 数据数组   * @param $where 过滤条件   * @return mixed 受影响记录   */  public function update($table, $data, $where)  {    foreach ($data as $key => $value) {      $data[$key] = $this->mysqli->real_escape_string($value);    }    $sets = array();    foreach ($data as $key => $value) {      $kstr = '`' . $key . '`';      $vstr = '/'' . $value . '/'';      array_push($sets, $kstr . '=' . $vstr);    }    $kav = implode(',', $sets);    $sql = "UPDATE {$table} SET {$kav} WHERE {$where}";    $this->mysqli->query($sql);    return $this->mysqli->affected_rows;  }  /**   * 删除数据   * @param $table 数据表   * @param $where 过滤条件   * @return mixed 受影响记录   */  public function delete($table, $where)  {    $sql = "DELETE FROM {$table} WHERE {$where}";    $this->mysqli->query($sql);    return $this->mysqli->affected_rows;  }}

<?phprequire_once 'mysql.class.php';/* 配置连接参数 */$config = array(  'type' => 'mysql',  'host' => 'localhost',  'username' => 'woider',  'password' => '3243',  'database' => 'php',  'port' => '3306');/* 连接数据库 */$mysql = new mysql();$mysql->connect($config);/* 查询数据 *///1、查询所有数据$table = 'mysqli';//数据表$num = $mysql->select($table);echo '共查询到' . $num . '条数据';print_r($mysql->fetchAll());//2、查询部分数据$field = array('username', 'password'); //过滤字段$where = 'id % 2 =0';          //过滤条件$mysql->select($table, $field, $where);print_r($mysql->fetchAll());/* 插入数据 */$table = 'mysqli';//数据表$data = array(  //数据数组  'username' => 'admin',  'password' => sha1('admin'));$id = $mysql->insert($table, $data);echo '插入记录的ID为' . $id;/* 修改数据 */$table = 'mysqli';//数据表$data = array(  'password' => sha1('nimda'));$where = 'id = 44';$rows = $mysql->update($table, $data, $where);echo '受影响的记录数量为' . $rows . '条';/* 删除数据 */$table = 'mysqli';$where = 'id = 45';$rows = $mysql->delete($table, $where);echo '已删除' . $rows . '条数据';