PDO database operation class

class HRDB{
 protected $pdo;
 protected $res;
 protected $config;

 /*constructor*/
 function __construct($config){
 $this->Config = $config;
 $this->connect();
 }

 /*Database connection*/
 public function connect(){
 $this->pdo = new PDO($this->Config['dsn'], $this->Config['name'], $this->Config['password']);
 $this->pdo->query('set names utf8;');
 //Put the result Serialized into stdClass
 //$this->pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);
 //Write your own code to catch Exception
 $this->pdo->setAttribute(PDO: :ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 }

 /*Database close*/
 public function close(){
 $this->pdo = null;
 }

 public function query($sql){
 $ res = $this->pdo->query($sql);
 if($res){
 $this->res = $res;
 }
 }
 public function exec($sql){
 $ res = $this->pdo->exec($sql);
 if($res){
 $this->res = $res;
 }
 }
 public function fetchAll(){
 return $this ->res->fetchAll();
 }
 public function fetch(){
 return $this->res->fetch();
 }
 public function fetchColumn(){
 return $this-> ;res->fetchColumn();
 }
 public function lastInsertId(){
 return $this->res->lastInsertId();
 }

 /**
 * Parameter Description
 * int $debug Whether to enable debugging, if enabled, the sql statement will be output
 * 0 Do not enable
 * 1 Enable
 * 2 Enable and terminate the program
 * int $mode Return type
 * 0 Return multiple records
 * 1 Returns a single record
 * 2 Returns the number of rows
 * string/array $table database table, two value-passing modes
 * Normal mode:
 * 'tb_member, tb_money'
 * Array mode:
 * array('tb_member', 'tb_money')
 * string/array $fields Database fields to be queried, allowed to be empty, default is to find all, two value-passing modes
 * Normal mode:
 * 'username, password'
 * Array mode:
 * array('username', 'password')
 * string/array $sqlwhere query conditions, empty allowed, two value-passing modes
 * Normal mode:
 * 'and type = 1 and username like "%os%"'
 * Array mode:
 * array('type = 1', 'username like "%os%"')
 * string $orderby sorting, the default is id reverse order
*/
 public function select( $debug, $mode, $table, $fields="*", $sqlwhere="", $orderby="tbid desc"){
 //Parameter processing
 if(is_array($table)){
 $table = implode(', ', $table);
 }
 if(is_array($fields)){
 $fields = implode(', ', $fields);
 }
 if(is_array($sqlwhere)){
 $ sqlwhere = ' and '.implode(' and ', $sqlwhere);
 }
 //Database operation
 if($debug === 0){
 if($mode === 2){
 $this-> ;query("select count(tbid) from $table where 1=1 $sqlwhere");
 $return = $this->fetchColumn();
 }else if($mode === 1){
 $this ->query("select $fields from $table where 1=1 $sqlwhere order by $orderby");
 $return = $this->fetch();
 }else{
 $this->query( "select $fields from $table where 1=1 $sqlwhere order by $orderby");
 $return = $this->fetchAll();
 }
 return $return;
 }else{
 if($mode = == 2){
 echo "select count(tbid) from $table where 1=1 $sqlwhere";
 }else if($mode === 1){
 echo "select $fields from $table where 1=1 $sqlwhere order by $orderby";
 }
            else{
                echo "select $fields from $table where 1=1 $sqlwhere order by $orderby";
            }
            if($debug === 2){
                exit;
            }
        }
    }

    /**
 * Parameter Description
 * int $debug Whether to enable debugging, if enabled, the sql statement will be output
 * 0 Do not enable
 * 1 Enable
 * 2 Enable and terminate the program
 * int $mode Return type
 * 0 No return information
 * 1 Returns the number of execution entries
 * 2 Returns the id of the last inserted record
 * string/array $table database table, two value-passing modes
 * Normal mode:
 * 'tb_member, tb_money'
 * Array mode:
 * array( 'tb_member', 'tb_money')
 * string/array $set Fields and contents to be inserted, two value-passing modes
 * Normal mode:
 * 'username = "test", type = 1, dt = now() '
 * Array mode:
 * array('username = "test"', 'type = 1', 'dt = now()')
*/
    public function insert($debug, $mode, $table, $set){
        //参数处理
        if(is_array($table)){
            $table = implode(', ', $table);
        }
        if(is_array($set)){
            $set = implode(', ', $set);
        }
        //数据库操作
        if($debug === 0){
            if($mode === 2){
                $this->query("insert into $table set $set");
                $return = $this->lastInsertId();
            }else if($mode === 1){
                $this->exec("insert into $table set $set");
                $return = $this->res;
            }else{
                $this->query("insert into $table set $set");
                $return = NULL;
            }
            return $return;
        }else{
            echo "insert into $table set $set";
            if($debug === 2){
                exit;
            }
        }
    }

    /**
 * Parameter Description
 * int $debug Whether to enable debugging, if enabled, the sql statement will be output
 * 0 Do not enable
 * 1 Enable
 * 2 Enable and terminate the program
 * int $mode Return type
 * 0 No return information
 * 1 Returns the number of execution entries
 * string $table database table, two value-passing modes
 * Normal mode:
 * 'tb_member, tb_money'
 * Array mode:
 * array('tb_member', 'tb_money')
 * string/ array $set Fields and contents that need to be updated, two value-passing modes
 * Normal mode:
 * 'username = "test", type = 1, dt = now()'
 * Array mode:
 * array('username = "test"', 'type = 1', 'dt = now()')
 * string/array $sqlwhere Modify the conditions, allow empty, two value-passing modes
 * Normal mode:
 * 'and type = 1 and username like "%os%"'
 * Array mode:
 * array('type = 1', 'username like "%os%"')
*/
    public function update($debug, $mode, $table, $set, $sqlwhere=""){
        //参数处理
        if(is_array($table)){
            $table = implode(', ', $table);
        }
        if(is_array($set)){
            $set = implode(', ', $set);
        }
        if(is_array($sqlwhere)){
            $sqlwhere = ' and '.implode(' and ', $sqlwhere);
        }
        //数据库操作
        if($debug === 0){
            if($mode === 1){
                $this->exec("update $table set $set where 1=1 $sqlwhere");
                $return = $this->res;
            }else{
                $this->query("update $table set $set where 1=1 $sqlwhere");
                $return = NULL;
            }
            return $return;
        }else{
            echo "update $table set $set where 1=1 $sqlwhere";
            if($debug === 2){
                exit;
            }
        }
    }

    /**
 * Parameter Description
 * int $debug Whether to enable debugging, if enabled, the sql statement will be output
 * 0 Do not enable
 * 1 Enable
 * 2 Enable and terminate the program
 * int $mode Return type
 * 0 No return information
 * 1 Returns the number of execution entries
 * string $table database table
 * string/array $sqlwhere deletion condition, allowed to be empty, two value-passing modes
 * Normal mode:
 * 'and type = 1 and username like "%os%" '
 * Array mode:
 * array('type = 1', 'username like "%os%"')
*/
    public function delete($debug, $mode, $table, $sqlwhere=""){
        //参数处理
        if(is_array($sqlwhere)){
            $sqlwhere = ' and '.implode(' and ', $sqlwhere);
        }
        //数据库操作
        if($debug === 0){
            if($mode === 1){
                $this->exec("delete from $table where 1=1 $sqlwhere");
                $return = $this->res;
            }else{
                $this->query("delete from $table where 1=1 $sqlwhere");
                $return = NULL;
            }
            return $return;
        }else{
            echo "delete from $table where 1=1 $sqlwhere";
            if($debug === 2){
                exit;
            }
        }
    }
}

PDO