odbc_binmode

(PHP 4, PHP 5, PHP 7)

odbc_binmodeHandling of binary column data

说明

odbc_binmode ( resource $result_id , int $mode ) : bool

Controls handling of binary column data. ODBC SQL types affected are BINARY, VARBINARY, and LONGVARBINARY. The default mode can be set using the uodbc.defaultbinmode php.ini directive.

When binary SQL data is converted to character C data (ODBC_BINMODE_CONVERT), 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".

While the handling of BINARY and VARBINARY columns only depend on the binmode, the handling of LONGVARBINARY columns also depends on the longreadlen as well:

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_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 odbc_result() is used, passthru means that the data are sent directly to the client (i.e. printed).

参数

result_id

The result identifier.

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

mode

Possible values for mode are:

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

Note: Handling of binary long columns is also affected by odbc_longreadlen().

返回值

成功时返回 TRUE, 或者在失败时返回 FALSE

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User Contributed Notes 4 notes

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1
yhalmoe at yahoo dot no
10 years ago
For Sybase users (this probably applies to MS-SQL Server as well) who are using ODBC:

I was using the same code as mizmerize, but I was getting truncated data back from the server (at the 32kb mark) when selecting data with the image datatype. My Sybase server has a @@textsize property of 2Gb, which should be plenty. But apparently, the php ODBC driver resets this to 32Kb when a connection is made, and then sets it back to 2Gb after. The solution is to do a query:

<?php odbc_exec($connH, "set textsize 131072"); ?>

immediately before your main query, in mizmerize's code. That should override the default setting.
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0
mizmerize at yahoo dot com
14 years ago
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...
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0
andrea dot galli at acotel dot com
17 years ago
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;

?>
up
-1
bortuzar
11 years ago
I set the odbc_longreadlen() at the beggining of my script so nText field types dont get truncated, like this:

<?php odbc_longreadlen (0, 1000000); ?>
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