PHP-MySQL 数据库操作类

2023-01-11
38.50k 字

前言

这个类封装了对 MySQL 数据库的常用操作，主要优势有：

  1. 简化了操作步骤：使用这个类可以简化对数据库的操作，只需要调用相应的方法即可完成增删改查等常见操作。
  2. 防止 SQL 注入：使用这个类可以有效防止 SQL 注入攻击，通过在拼接 SQL 语句时对特殊字符进行转义，避免了手动拼接 SQL 语句时的安全隐患。
  3. 方便地进行数据排序和筛选：通过提供Sort和Filter方法, 可以方便的对数组进行排序和筛选

  4. 处理离线或超时连接：通过在操作前检查连接是否有效, 如果失效就重新连接,避免出现离线或超时的错误.

    函数说明

    construct

    方法用于在创建 Mysql 类的新实例时初始化连接到 MySQL 服务器所需的信息。
    更具体地说, 它在类初始化时需要一个配置数组作为参数, 这个数组包含连接到 MySQL 服务器所需的主机名,用户名,密码,数据库名称和超时时间。
    构造函数会把这些信息保存到类的私有变量中,并且使用这些变量来创建连接数据库的实例. 如果连接失败，则会打印一条消息并终止程序运行。

     public function __construct($config) {
     $this->host = $config['host'];
     $this->username = $config['username'];
     $this->password = $config['password'];
     $this->database = $config['database'];
     $this->timeout  = $config['timeout']; 
     $this->conn = new mysqli($this->host, $this->username, $this->password, $this->database);
     if ($this->conn->connect_error) {
         die('Connection failed: ' . $this->conn->connect_error);
     }
     $this->conn->options(MYSQLI_OPT_CONNECT_TIMEOUT, $this->timeout);  
 }

    Operate

     public function Operate($data) {
     //检查连接是否有效
     if(!$this->conn->ping()) {
         $this->conn->close();
         $this->conn = mysqli_init();
         mysqli_options($this->conn, MYSQLI_OPT_CONNECT_TIMEOUT, $this->timeout);
         if(!mysqli_real_connect($this->conn, $this->host, $this->username, $this->password, $this->database)) {
             throw new Exception('Error: '.mysqli_connect_error());
         }
     }
     //验证数组合法性
     $ArrayKeyJoining = $this->ArrayKeyJoining($data);
     $ArrayKeyJoining = str_replace(".Sort", "", $ArrayKeyJoining);

     switch ($ArrayKeyJoining) {
         case 'Insert.Table.Data':
             # 增与批量增
             $Sql = $this->SqlStr($data,'Insert');
             $type = 'Num';
             break;
          case 'Delete.Table.Key.KeyValue':
             # 主键删除
             $Sql = $this->SqlStr($data,'Delete','Key');
             $type = 'Num';
             break;
          case 'Delete.Table.Filter':
             # 条件删除
             $Sql = $this->SqlStr($data,'Delete','Filter');
             $type = 'Num';
             break;
          case 'Modify.Table.Key.KeyValue.Data':
             # 主键改
             $Sql = $this->SqlStr($data,'Modify','Key');
             $type = 'Num';
             break;
          case 'Modify.Table.Filter.Data':
             # 筛选改
             $Sql = $this->SqlStr($data,'Modify','Filter');
             $type = 'Num';
             //var_dump($Sql);die();
             break;
          case 'Query.Table.Num.Filter':
             # 查询
             $Sql = $this->SqlStr($data,'Query');
             $type = 'Result';
             //var_dump($Sql);die();
             break;
          case 'Query.Table.Num.Page.Filter':
             # 分页查询
             $Sql = $this->SqlStr($data,'Query','Pag');
             $type = 'Pag';
             break;
         default:
             return ['State' => false,'error' => '传递参数错误'];
             break;
     }
     // 执行操作 无需返回数据
     if ($type == 'Num') {
         if ($this->conn->query($Sql) === TRUE) {
             return ['State' => TRUE,'Message' => $this->conn->affected_rows];
         } else {
             return ['State' => false,'error' => $this->conn->error];
         }
     }
     // 执行操作 只需返回数据
     if ($type == 'Result') {
         // 执行查询
         $result = $this->conn->query($Sql);
         if ($result === false) {
             return ['State' => false,'error' => $this->conn->error];
         }
         // 将查询结果转换为数组
         $rows = [];
         while ($row = $result->fetch_assoc()) {
             $rows[] = $row;
         }
         return ['State' => TRUE,'Data' => $rows];
     }
     //执行操作 分页
     if ($type == 'Pag') {
         // 执行查询
         $result = $this->conn->query($Sql['Sql']);
         if ($result === false) {
             return ['State' => false,'error' => $this->conn->error];
         }
         // 将查询结果转换为数组
         $rows = [];
         while ($row = $result->fetch_assoc()) {
             $rows[] = $row;
         }
         // 获取总记录数
         $totalResult = $this->conn->query($Sql['SqlTotal']);
         $totalRow = $totalResult->fetch_assoc();

         $total = $totalRow['COUNT'];//数据总量
         // 计算总页数 
         $totalPages = ceil($total / $data['Query']['Num']);
         return ['State' => TRUE,'Total' =>$total, 'PageCount' =>$totalPages,'Current' =>$data['Query']['Page'],'Num' => $data['Query']['Num'],'Data' => $rows];
     }
 }

    SqlStr

     public function SqlStr($data,$type,$Class = '') {
         // var_dump($data[$type]);die();
         $escapedValues = $this->EscapeStrings($data[$type]);
         //var_dump($escapedValues);
         $Table = $escapedValues["Table"];//表名称

         // 准备增Sql语句
         if ($type == 'Insert') {
             //获取字段
             $Field = array_keys($escapedValues["Data"][0]);
             $FieldStr = implode(',', $Field);
             //获取值
             $Value = [];
             foreach ($escapedValues["Data"] as $value) {
                 $Value[] = "('" . implode("','", $value) . "')";
             }
             $ValueStr = implode(',', $Value);
             return "INSERT INTO `$Table` ($FieldStr) VALUES $ValueStr";
         }
         // 准备主键删除Sql语句
         if ($type == 'Delete' && $Class == 'Key') {
             $Key = $escapedValues["Key"];//获取主键
             //获取值
             $Value = [];
             foreach ($escapedValues["KeyValue"] as $value) {
                 $Value[] = $value;
             }
             $ValueStr = implode(',', $Value);
             return "DELETE FROM `$Table` WHERE `$Key` IN ($ValueStr)";
         }
         // 准备条件删除Sql语句
         if ($type == 'Delete' && $Class == 'Filter') {
             $Filter = $this->Filter($escapedValues['Filter']);//筛选条件
             return "DELETE FROM `$Table` WHERE $Filter";
         }
         // 准备主键修改Sql语句
         if ($type == 'Modify' && $Class == 'Key') {
             $Key = $escapedValues["Key"];//获取主键
             $KeyValue=[];
             foreach ($escapedValues["KeyValue"] as $value) {
                 if (!is_numeric($value)) {
                     die('error: 主键值只能是int');
                 }
                 $KeyValue[]=$value;
             }
             $KeyStr = implode(',', $KeyValue);
             $DataValue=[];
             foreach ($escapedValues["Data"] as $key => $value) {
                 $DataValue[]= "`".$key."` = '".$value."'";
             }
             $DataStr = implode(' , ', $DataValue);
             return "UPDATE `$Table` SET $DataStr WHERE $Key IN ($KeyStr)";
         }
         //准备条件修改SQL语句
         if ($type == 'Modify' && $Class == 'Filter') {
             $Filter = $this->Filter($escapedValues['Filter']);//筛选条件

             $DataValue=[];
             foreach ($escapedValues["Data"] as $key => $value) {
                 $DataValue[]= "`".$key."` = '".$value."'";
             }
             $DataStr = implode(' , ', $DataValue);
             return "UPDATE `$Table` SET $DataStr WHERE $Filter";
         }
         //准备查询Sql语句
         if ($type == 'Query' && $Class == '') {
             $Num = $escapedValues["Num"];//获取条数
             if (!is_int($Num)) {
                 die('error: Num只能是INT');
             }
             $Filter = $this->Filter($escapedValues['Filter']);//筛选条件

             $Sort ='';
             if (isset($escapedValues["Sort"])) {
                $Sort =  $this->Sort($escapedValues['Sort']);//排序
             }
             return "SELECT * FROM `$Table` WHERE $Filter $Sort LIMIT $Num";
         }
         //准备分页查询Sql语句
         if ($type == 'Query' && $Class == 'Pag') {
             $Page = $escapedValues["Page"];//获取当前页
             $Num = $escapedValues["Num"];//获取条数
             if (!is_int($Num) && !is_int($Page) ) {
                 die('error: Num与Page只能是INT');
             }
             $offset = ($Page - 1) * $Num;//计算起始条数
             $Filter = $this->Filter($escapedValues['Filter']);//筛选条件

             $Sort ='';
             if (isset($escapedValues["Sort"])) {
                $Sort =  $this->Sort($escapedValues['Sort']);//排序
             }
             return ['Sql' => "SELECT * FROM `$Table` WHERE $Filter $Sort LIMIT $offset,$Num" , 'SqlTotal'=>"SELECT COUNT(*) AS COUNT  FROM `$Table` WHERE $Filter"];
         }

         $this->conn->close();
 }

    其他辅助函数

    //组装排序
 public function Sort($Sort){

     if (count($Sort) >=3) {
         die('error: 排序参数超过两个');
     }elseif (count($Sort) == 1) {
          return " ORDER BY `$Sort[0]`";
     }elseif (count($Sort) == 2) {
          if ($Sort[1] == 'DESC' || $Sort[1] == 'ASC') {
              return " ORDER BY `$Sort[0]` $Sort[1]";
          }else{
              die('error: 排序类型只能是DESC或ASC');
          }
     }else{
         die('error: 排序参数错误');
     }
 }
 //组装筛选条件
 public function Filter($Filter){
     $FilterArray=[];
     foreach ($Filter as $value) {
         if (count($value) == 1) {
             if ($value[0] == 'AND' OR $value[0] == 'OR' ) {
                 $FilterArray[]=$value[0];
             }else{
                die('error: 筛选连接符只能是AND或OR');
             }
         } else if (count($value) == 3) {
             $FilterArray[] = '`'.$value[0].'`' . ' ' . $value[1] . " '" . $value[2]."'";
         }else {
               die('error: 筛选值不正确');
         }
     }
     // 将数组中的元素用 AND 或 OR 连接起来
     return implode(' ', $FilterArray);
 }
 //检测字符串合法性方法
 public function ArrayKeyJoining($data){
     if ($this->is_2d_array($data)) {
         $ArrayKeyJoining='';
         foreach ($data as $key_1 => $value_1) {
             $ArrayKeyJoining .=$key_1;
             foreach ($value_1 as $key_2 => $value_2) {
                 $ArrayKeyJoining .='.'.$key_2;
             }
             if (!is_string($data[$key_1]['Table'])) {
                     die('error: Table只能是字符串');
              }
         }
         return $ArrayKeyJoining;
     }else{
         die('error: 传递参数必须是一个二维数组');
     }
 }
 //转义数组中的每个字符串方法 起到预防sql攻击
 private function EscapeStrings($data) {
     if (is_array($data)) {
         $escapedData = [];
         foreach ($data as $key => $value) {
             $escapedData[$key] = $this->escapeStrings($value);
         }
         return $escapedData;
     } else if (is_string($data)) {
         return $this->conn->real_escape_string($data);
     } else {
         return $data;
     }
 }
 //判断是否是二维数组方法
 public function is_2d_array($arr) {
     if (!is_array($arr)) {
         return false;
     }
     foreach ($arr as $item) {
         if (!is_array($item)) {
             return false;
         }
     }
     return true;
 }

    调用数组

    // 增
$data = ['operation' => 'Insert','table' => 'TableName','data' => [
     ['ip_id' => 888, 'address_id' => 88, 'isp_id' => 88],
     ['ip_id' => 6, 'address_id' => 666, 'isp_id' => 666],
 ]
];
// 删
$data = ['operation' => 'Delete','table' => 'TableName','filter' => [
     ['ip_id', '>=', 888],
     ['AND'],
     ['ip_id', '<=', 98248429]
 ]
];
$data = ['operation' => 'Delete','table' => 'TableName','key' => 'ip_id','key_value' => [1, 2, 3, 4, 5, 6],];
// 改
$data = ['operation' => 'Modify','table' => 'TableName','filter' => [
     ['ip_id', '=', 167292492],
     ['OR'],
     ['ip_id', '=', 501131500],
 ],
 'data' => [
     'address_id' => 'asdasd', 
 ]
];
$data = ['operation' => 'Modify','table' => 'TableName','key' => 'ip_id','key_value' => [326165381, 368344353, 501131500],
 'data' => ['address_id' => 6,]
];
// 查
$data = ['operation' => 'Query','table' => 'TableName','num' => 10,'filter' => [
     ['ip_id', '>', 167292492],
     ['AND'],
     ['ip_id', '<', 784746588],
 ],
 'sort' => ['ip_id', 'DESC']
];
$data = ['operation' => 'Query','table' => 'TableName','num' => 2,'page' => 3,'filter' => [
     ['ip_id', '>', 167292492],
     ['AND'],
     ['ip_id', '<', 1002378841],
 ],
 'sort' => ['ip_id', 'DESC']
];

    完整代码

class Mysql {
  private $host;
  private $username;
  private $password;
  private $database;
  private $conn;
  private $timeout; //超时时间变量

  public function __construct( $config ) {
    // 从配置数组中获取数据库连接信息
    $this->host = $config[ 'host' ];
    $this->username = $config[ 'username' ];
    $this->password = $config[ 'password' ];
    $this->database = $config[ 'database' ];
    $this->timeout = $config[ 'timeout' ]; //获取超时时间
    // 创建数据库连接
    $this->conn = new mysqli( $this->host, $this->username, $this->password, $this->database );
    if ( $this->conn->connect_error ) {
      die( 'Connection failed: ' . $this->conn->connect_error );
    }
    $this->conn->options( MYSQLI_OPT_CONNECT_TIMEOUT, $this->timeout ); //设置超时时间
  }
  //操作
  public function Operate( $data ) {
    //检查连接是否有效
    if ( !$this->conn->ping() ) {
      $this->conn->close();
      $this->conn = mysqli_init();
      mysqli_options( $this->conn, MYSQLI_OPT_CONNECT_TIMEOUT, $this->timeout );
      if ( !mysqli_real_connect( $this->conn, $this->host, $this->username, $this->password, $this->database ) ) {
        throw new Exception( 'Error: ' . mysqli_connect_error() );
      }
    }
    //验证数组合法性
    $ArrayKeyJoining = $this->ArrayKeyJoining( $data );
    $ArrayKeyJoining = str_replace( ".Sort", "", $ArrayKeyJoining );

    switch ( $ArrayKeyJoining ) {
      case 'Insert.Table.Data':
        # 增与批量增
        $Sql = $this->SqlStr( $data, 'Insert' );
        $type = 'Num';
        break;
      case 'Delete.Table.Key.KeyValue':
        # 主键删除
        $Sql = $this->SqlStr( $data, 'Delete', 'Key' );
        $type = 'Num';
        break;
      case 'Delete.Table.Filter':
        # 条件删除
        $Sql = $this->SqlStr( $data, 'Delete', 'Filter' );
        $type = 'Num';
        break;
      case 'Modify.Table.Key.KeyValue.Data':
        # 主键改
        $Sql = $this->SqlStr( $data, 'Modify', 'Key' );
        $type = 'Num';
        break;
      case 'Modify.Table.Filter.Data':
        # 筛选改
        $Sql = $this->SqlStr( $data, 'Modify', 'Filter' );
        $type = 'Num';
        //var_dump($Sql);die();
        break;
      case 'Query.Table.Num.Filter':
        # 查询
        $Sql = $this->SqlStr( $data, 'Query' );
        $type = 'Result';
        //var_dump($Sql);die();
        break;
      case 'Query.Table.Num.Page.Filter':
        # 分页查询
        $Sql = $this->SqlStr( $data, 'Query', 'Pag' );
        $type = 'Pag';
        break;
      default:
        return [ 'State' => false, 'error' => '传递参数错误' ];
        break;
    }
    // 执行操作 无需返回数据
    if ( $type == 'Num' ) {
      if ( $this->conn->query( $Sql ) === TRUE ) {
        return [ 'State' => TRUE, 'Message' => $this->conn->affected_rows ];
      } else {
        return [ 'State' => false, 'error' => $this->conn->error ];
      }
    }
    // 执行操作 只需返回数据
    if ( $type == 'Result' ) {
      // 执行查询
      $result = $this->conn->query( $Sql );
      if ( $result === false ) {
        return [ 'State' => false, 'error' => $this->conn->error ];
      }
      // 将查询结果转换为数组
      $rows = [];
      while ( $row = $result->fetch_assoc() ) {
        $rows[] = $row;
      }
      return [ 'State' => TRUE, 'Data' => $rows ];
    }
    //执行操作 分页
    if ( $type == 'Pag' ) {
      // 执行查询
      $result = $this->conn->query( $Sql[ 'Sql' ] );
      if ( $result === false ) {
        return [ 'State' => false, 'error' => $this->conn->error ];
      }
      // 将查询结果转换为数组
      $rows = [];
      while ( $row = $result->fetch_assoc() ) {
        $rows[] = $row;
      }
      // 获取总记录数
      $totalResult = $this->conn->query( $Sql[ 'SqlTotal' ] );
      $totalRow = $totalResult->fetch_assoc();

      $total = $totalRow[ 'COUNT' ]; //数据总量
      // 计算总页数 
      $totalPages = ceil( $total / $data[ 'Query' ][ 'Num' ] );
      return [ 'State' => TRUE, 'Total' => $total, 'PageCount' => $totalPages, 'Current' => $data[ 'Query' ][ 'Page' ], 'Num' => $data[ 'Query' ][ 'Num' ], 'Data' => $rows ];
    }
  }
  //拼接SQL语句
  public function SqlStr( $data, $type, $Class = '' ) {
    // var_dump($data[$type]);die();
    $escapedValues = $this->EscapeStrings( $data[ $type ] );
    //var_dump($escapedValues);
    $Table = $escapedValues[ "Table" ]; //表名称

    // 准备增Sql语句
    if ( $type == 'Insert' ) {
      //获取字段
      $Field = array_keys( $escapedValues[ "Data" ][ 0 ] );
      $FieldStr = implode( ',', $Field );
      //获取值
      $Value = [];
      foreach ( $escapedValues[ "Data" ] as $value ) {
        $Value[] = "('" . implode( "','", $value ) . "')";
      }
      $ValueStr = implode( ',', $Value );
      return "INSERT INTO `$Table` ($FieldStr) VALUES $ValueStr";
    }
    // 准备主键删除Sql语句
    if ( $type == 'Delete' && $Class == 'Key' ) {
      $Key = $escapedValues[ "Key" ]; //获取主键
      //获取值
      $Value = [];
      foreach ( $escapedValues[ "KeyValue" ] as $value ) {
        $Value[] = $value;
      }
      $ValueStr = implode( ',', $Value );
      return "DELETE FROM `$Table` WHERE `$Key` IN ($ValueStr)";
    }
    // 准备条件删除Sql语句
    if ( $type == 'Delete' && $Class == 'Filter' ) {
      $Filter = $this->Filter( $escapedValues[ 'Filter' ] ); //筛选条件
      return "DELETE FROM `$Table` WHERE $Filter";
    }
    // 准备主键修改Sql语句
    if ( $type == 'Modify' && $Class == 'Key' ) {
      $Key = $escapedValues[ "Key" ]; //获取主键
      $KeyValue = [];
      foreach ( $escapedValues[ "KeyValue" ] as $value ) {
        if ( !is_numeric( $value ) ) {
          die( 'error: 主键值只能是int' );
        }
        $KeyValue[] = $value;
      }
      $KeyStr = implode( ',', $KeyValue );
      $DataValue = [];
      foreach ( $escapedValues[ "Data" ] as $key => $value ) {
        $DataValue[] = "`" . $key . "` = '" . $value . "'";
      }
      $DataStr = implode( ' , ', $DataValue );
      return "UPDATE `$Table` SET $DataStr WHERE $Key IN ($KeyStr)";
    }
    //准备条件修改SQL语句
    if ( $type == 'Modify' && $Class == 'Filter' ) {
      $Filter = $this->Filter( $escapedValues[ 'Filter' ] ); //筛选条件

      $DataValue = [];
      foreach ( $escapedValues[ "Data" ] as $key => $value ) {
        $DataValue[] = "`" . $key . "` = '" . $value . "'";
      }
      $DataStr = implode( ' , ', $DataValue );
      return "UPDATE `$Table` SET $DataStr WHERE $Filter";
    }
    //准备查询Sql语句
    if ( $type == 'Query' && $Class == '' ) {
      $Num = $escapedValues[ "Num" ]; //获取条数
      if ( !is_int( $Num ) ) {
        die( 'error: Num只能是INT' );
      }
      $Filter = $this->Filter( $escapedValues[ 'Filter' ] ); //筛选条件

      $Sort = '';
      if ( isset( $escapedValues[ "Sort" ] ) ) {
        $Sort = $this->Sort( $escapedValues[ 'Sort' ] ); //排序
      }
      return "SELECT * FROM `$Table` WHERE $Filter $Sort LIMIT $Num";
    }
    //准备分页查询Sql语句
    if ( $type == 'Query' && $Class == 'Pag' ) {
      $Page = $escapedValues[ "Page" ]; //获取当前页
      $Num = $escapedValues[ "Num" ]; //获取条数
      if ( !is_int( $Num ) && !is_int( $Page ) ) {
        die( 'error: Num与Page只能是INT' );
      }
      $offset = ( $Page - 1 ) * $Num; //计算起始条数
      $Filter = $this->Filter( $escapedValues[ 'Filter' ] ); //筛选条件

      $Sort = '';
      if ( isset( $escapedValues[ "Sort" ] ) ) {
        $Sort = $this->Sort( $escapedValues[ 'Sort' ] ); //排序
      }
      return [ 'Sql' => "SELECT * FROM `$Table` WHERE $Filter $Sort LIMIT $offset,$Num", 'SqlTotal' => "SELECT COUNT(*) AS COUNT  FROM `$Table` WHERE $Filter" ];
    }

    $this->conn->close();
  }
  //组装排序
  public function Sort( $Sort ) {

    if ( count( $Sort ) >= 3 ) {
      die( 'error: 排序参数超过两个' );
    } elseif ( count( $Sort ) == 1 ) {
      return " ORDER BY `$Sort[0]`";
    } elseif ( count( $Sort ) == 2 ) {
      if ( $Sort[ 1 ] == 'DESC' || $Sort[ 1 ] == 'ASC' ) {
        return " ORDER BY `$Sort[0]` $Sort[1]";
      } else {
        die( 'error: 排序类型只能是DESC或ASC' );
      }
    } else {
      die( 'error: 排序参数错误' );
    }
  }
  //组装筛选条件
  public function Filter( $Filter ) {
    $FilterArray = [];
    foreach ( $Filter as $value ) {
      if ( count( $value ) == 1 ) {
        if ( $value[ 0 ] == 'AND'
          OR $value[ 0 ] == 'OR' ) {
          $FilterArray[] = $value[ 0 ];
        } else {
          die( 'error: 筛选连接符只能是AND或OR' );
        }
      } else if ( count( $value ) == 3 ) {
        $FilterArray[] = '`' . $value[ 0 ] . '`' . ' ' . $value[ 1 ] . " '" . $value[ 2 ] . "'";
      } else {
        die( 'error: 筛选值不正确' );
      }
    }
    // 将数组中的元素用 AND 或 OR 连接起来
    return implode( ' ', $FilterArray );
  }
  //检测字符串合法性方法
  public function ArrayKeyJoining( $data ) {
    if ( $this->is_2d_array( $data ) ) {
      $ArrayKeyJoining = '';
      foreach ( $data as $key_1 => $value_1 ) {
        $ArrayKeyJoining .= $key_1;
        foreach ( $value_1 as $key_2 => $value_2 ) {
          $ArrayKeyJoining .= '.' . $key_2;
        }
        if ( !is_string( $data[ $key_1 ][ 'Table' ] ) ) {
          die( 'error: Table只能是字符串' );
        }
      }
      return $ArrayKeyJoining;
    } else {
      die( 'error: 传递参数必须是一个二维数组' );
    }
  }
  //转义数组中的每个字符串方法 起到预防sql攻击
  private function EscapeStrings( $data ) {
    if ( is_array( $data ) ) {
      $escapedData = [];
      foreach ( $data as $key => $value ) {
        $escapedData[ $key ] = $this->escapeStrings( $value );
      }
      return $escapedData;
    } else if ( is_string( $data ) ) {
      return $this->conn->real_escape_string( $data );
    } else {
      return $data;
    }
  }
  //判断是否是二维数组方法
  public function is_2d_array( $arr ) {
    if ( !is_array( $arr ) ) {
      return false;
    }
    foreach ( $arr as $item ) {
      if ( !is_array( $item ) ) {
        return false;
      }
    }
    return true;
  }

}