odbc_binmode
(PHP 4, PHP 5)
odbc_binmode — Handling of binary column data
Описание
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".
| 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.
Список параметров
- result_id
-
The result identifier.
If result_id is 0, the settings apply as default for new results.
Замечание: 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
Возвращаемые значения
Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения для работы с базами данных
- Уровни абстракции
- ODBC (Unified)
- odbc_autocommit
- odbc_binmode
- odbc_close_all
- odbc_close
- odbc_columnprivileges
- odbc_columns
- odbc_commit
- odbc_connect
- odbc_cursor
- odbc_data_source
- odbc_do
- odbc_error
- odbc_errormsg
- odbc_exec
- odbc_execute
- odbc_fetch_array
- odbc_fetch_into
- odbc_fetch_object
- odbc_fetch_row
- odbc_field_len
- odbc_field_name
- odbc_field_num
- odbc_field_precision
- odbc_field_scale
- odbc_field_type
- odbc_foreignkeys
- odbc_free_result
- odbc_gettypeinfo
- odbc_longreadlen
- odbc_next_result
- odbc_num_fields
- odbc_num_rows
- odbc_pconnect
- odbc_prepare
- odbc_primarykeys
- odbc_procedurecolumns
- odbc_procedures
- odbc_result_all
- odbc_result
- odbc_rollback
- odbc_setoption
- odbc_specialcolumns
- odbc_statistics
- odbc_tableprivileges
- odbc_tables
Коментарии
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;
?>
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...
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); ?>
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.