odbc_binmode

(PHP 4, PHP 5)

odbc_binmode — Handling of binary column data

说明

bool odbc_binmode ( resource $result_id , int $mode )

Enables handling of binary column data. ODBC SQL types affected are BINARY, VARBINARY, and LONGVARBINARY.

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".

**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.

参数

result_id

The result identifier.

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

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

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

返回值

成功时返回 TRUE ，或者在失败时返回 FALSE 。

用户评论:

[#1] yhalmoe at yahoo dot no [2009-12-14 08:45:20]

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.

[#2] bortuzar [2009-02-12 07:28:49]

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); ?>

[#3] mizmerize at yahoo dot com [2006-01-10 18:59:34]

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...

[#4] andrea dot galli at acotel dot com [2003-04-28 08:27:29]

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; ?>