将PDF从tcpdf保存到数据库

Question

require_once('tcpdf/tcpdf.php');
  $conn=mysqli_connect("localhost","root","","courier_system");
  $uname='Honey';
  $con_id=2;
    $obj_pdf = new TCPDF(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);  
    $obj_pdf->SetCreator(PDF_CREATOR);  
    $obj_pdf->SetTitle("Consignment Receipt");  
    $obj_pdf->SetHeaderData('', '', PDF_HEADER_TITLE, PDF_HEADER_STRING);  
    $obj_pdf->setHeaderFont(Array(PDF_FONT_NAME_MAIN, '', PDF_FONT_SIZE_MAIN));  
    $obj_pdf->setFooterFont(Array(PDF_FONT_NAME_DATA, '', PDF_FONT_SIZE_DATA));  
    $obj_pdf->SetDefaultMonospacedFont('helvetica');  
    $obj_pdf->SetFooterMargin(PDF_MARGIN_FOOTER);  
    $obj_pdf->SetMargins(PDF_MARGIN_LEFT, '5', PDF_MARGIN_RIGHT);  
    $obj_pdf->setPrintHeader(false);  
    $obj_pdf->setPrintFooter(false);  
    $obj_pdf->SetAutoPageBreak(TRUE, 10);  
    $obj_pdf->SetFont('times', '', 14);  
    $obj_pdf->AddPage();
    $cotent='
    <div style="text-align:right;">
    <img width="100px" height="70px" src="images/logo.jpeg"></img>
        <h1 align="centre" style="color:blue;">Receipt</h1>
        <br/></div>
        <hr size="5px">';
    $obj_pdf->writeHTML($cotent);
    $cotent='<table width="100%">
                <tr>
                  <th width="50%">Order Date</th>
                  <th width="50%">Order ID</th>
                </tr>';
    $cotent.=fetch_data($uname,$cid);
    $cotent.='</table>';
    $obj_pdf->writeHTML($cotent);
    $connect = mysqli_connect("localhost", "root", "", "courier_system");  
    $sql = "SELECT * FROM consignment where user_name='$uname' and con_id=$cid";  
    $result = mysqli_query($connect, $sql);  
    $row=mysqli_fetch_assoc($result);
    $id=$row['branch_sou_id'];
    $cotent='<table width="100%">
                <tr>
                  <th width="50%">Branch Address:</th>
                </tr>';
    $cotent.=fetch_data1($id);
    $cotent.='</table><br/><br/><br/><br/>';
    $obj_pdf->writeHTML($cotent);
    $cotent='<table width="100%">
                <tr>
                  <th width="50%">From:</th>
                  <th width="50%">To:</th>
                </tr>';
    $cotent.=fetch_data2($uname,$cid);
    $cotent.='</table><br/><br/><br/><br/>';
    $obj_pdf->writeHTML($cotent);
    $obj_pdf->SetFont('times', '', 10);
    $cotent='
        <table border="1" cellspacing="0" cellpadding="5">
            <tr>
                <th width="10%">Sou Pincode</th>
                <th width="10%">Des Pincode</th>
                <th width="13%">Pickup Date</th>
                <th width="10%">Weight</th>
                <th width="10%">Mode</th>
                <th width="12%">Texable Value</th>
                <th width="14%">IGST</th>
                <th width="20%">Total</th>
            </tr>';
    $cotent.=fetch_data3($uname,$cid);
    $cotent.='</table><br/><br/><br/><br/>';
    $obj_pdf->writeHTML($cotent);
    $obj_pdf->SetFont('times', '', 14);
    $tax=0.12*$row['price'];
    $total=floor(0.5+$tax+$row['price']);
    $cotent='Total Price is Rs.'. $total;
    $obj_pdf->writeHTML($cotent);
    $cotent='The Price in Word '. getIndianCurrency($tax+$row['price']);
    $obj_pdf->writeHTML($cotent);
    $cotent='
    <div style="text-align:right;">
    <p style="font-size:16px">Signature</p>
    <img width="100px" height="70px" src="images/Signa.jpg"></img>
        </div>';
    $obj_pdf->writeHTML($cotent);
    $content=$obj_pdf->Output('', 'S');    
    //header("Content-type:application/pdf");
    //header("Content-Disposition:attachment;filename=pdf.pdf");
    //header("Location:abc.php?str='$sontent'");
    echo $content."<br/><br/><br/><br/>";
    // $data=file_get_contents('pdf.pdf');
    // echo $data;
    $sql="update consignment set receipt='$content' where con_id=4";
    if(mysqli_query($connect,$sql))
    {
      echo "hiiii";
    }
    else {
      echo "Error";
      echo mysqli_error($connect);
    }

The Photo of Error1

When I run then it will upload pdf file in the database. I am using PHPmyadmin database. In this code, the Invoice are generated and this pdf I want to upload in the database for the further use. But the error are generated from the Query that I am using. This PDF is generated using the TCPDF. In this, the detail are the come from the database at the run time using the PHP code. Thank You. Please Refer this Question