odbc_binmode

Description

bool odbc_binmode ( resource result_id, int mode )

(ODBC SQL types affected: BINARY, VARBINARY, LONGVARBINARY)

ODBC_BINMODE_PASSTHRU: Passthru BINARY data
ODBC_BINMODE_RETURN: Return as is
ODBC_BINMODE_CONVERT: Convert to char and return

When binary SQL data is converted to character C data, each byte (8 bits) of source data is represented as two ASCII characters. These characters are the ASCII character representation of the number in its hexadecimal form. For example, a binary 00000001 is converted to "01" and a binary 11111111 is converted to "FF".

表格 1. LONGVARBINARY handling

binmode	longreadlen	result
ODBC_BINMODE_PASSTHRU	0	passthru
ODBC_BINMODE_RETURN	0	passthru
ODBC_BINMODE_CONVERT	0	passthru
ODBC_BINMODE_PASSTHRU	0	passthru
ODBC_BINMODE_PASSTHRU	>0	passthru
ODBC_BINMODE_RETURN	>0	return as is
ODBC_BINMODE_CONVERT	>0	return as char

If odbc_fetch_into() is used, passthru means that an empty string is returned for these columns.

If result_id is 0, the settings apply as default for new results.

注: Default for longreadlen is 4096 and binmode defaults to ODBC_BINMODE_RETURN. Handling of binary long columns is also affected by odbc_longreadlen()

add a note User Contributed Notes

mizmerize at yahoo dot com
11-Jan-2006 10:59


I am currently using an SQL Server 2000 used as a datasource for ODBC access, Testing PHP scripts from an Apache 2 server running on Windows 2000.



I was trying to get an image from the database using ODBC but the output always flushes automatically while I was just getting the result using odbc_result() function.



With this code, the picture automatically prints to the browser as soon as I hit odbc_result() (probably a bug, but bug reports aren't that easy to do).



<?php

  $connH=odbc_pconnect("ImageDB","sa","",SQL_CUR_USE_IF_NEEDED) or die(odbc_errormsg());

    $result=odbc_exec($connH, "SELECT Emp_Image FROM tblEmployeePics WHERE Emp_Id=547");

    if ($result) {                            

        odbc_longreadlen($result, 131072);        

        odbc_binmode($result,ODBC_BINMODE_PASSTHRU);                            

//upon calling this, the output flushes out to the browser... made me scratch        

$m_FValue=odbc_result($result, 1);

}

?>



...after 48 hours of scratching I finally made a work around, but by using a function in the bin2hex() function documentation...



<?php

      function hex2bin($data){ 

       $len = strlen($data); 

       return pack("H" . $len, $data); 

    } 



    

    $connH=odbc_pconnect("ImageDB","sa","",SQL_CUR_USE_IF_NEEDED) or die(odbc_errormsg());

    $result=odbc_exec($connH, "SELECT Emp_Image FROM tblEmployeePics WHERE Emp_Id=547");

    if ($result) {                            

        odbc_longreadlen($result, 131072);        

        odbc_binmode($result,ODBC_BINMODE_CONVERT);                            

        $m_FValue=odbc_result($result, 1);

        $out=hex2bin($m_FValue);

    }

?>



The trick was to convert the output into hex by changing odbc_binmode to  ODBC_BINMODE_CONVERT and using a handy function to convert it back to binary in order to facilitate manipulation of its size, depth etc...

andrea dot galli at acotel dot com
28-Apr-2003 11:27


Example: retrieve image from database.



<?php



   $Link_ID = odbc_connect("DSN", "user", "pass"); 

   $Query_ID = odbc_exec($Link_ID, "SELECT picture FROM categories"); 



   // change to ODBC_BINMODE_CONVERT for comparison 



   odbc_binmode($Query_ID, ODBC_BINMODE_RETURN);



   $Images = odbc_result($Query_ID, 1);



   echo $Images;



?>

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