PostgreSQL 9.0 introduced "hex" as the new default format for encoding binary data. Because "pg_unescape_bytea" only works with the old "escape" format, you need to do pg_query('SET bytea_output = "escape";'); before executing your select queries.
More details can be found here: http://www.postgresql.org/docs/9.0/static/datatype-binary.html
[Ed: Recent PostgreSQL versions support unescaping the "hex" format.]
pg_unescape_bytea
(PHP 4 >= 4.3.0, PHP 5, PHP 7)
pg_unescape_bytea — Unescape binary for bytea type
Opis
pg_unescape_bytea
( string
$data
) : stringpg_unescape_bytea() unescapes PostgreSQL bytea data values. It returns the unescaped string, possibly containing binary data.
Informacja:
When you SELECT a bytea type, PostgreSQL returns octal byte values prefixed with '\' (e.g. \032). Users are supposed to convert back to binary format manually.
This function requires PostgreSQL 7.2 or later. With PostgreSQL 7.2.0 and 7.2.1, bytea values must be cast when you enable multi-byte support. i.e. INSERT INTO test_table (image) VALUES ('$image_escaped'::bytea); PostgreSQL 7.2.2 or later does not need a cast. The exception is when the client and backend character encoding does not match, and there may be multi-byte stream error. User must then cast to bytea to avoid this error.
Zwracane wartości
A string containing the unescaped data.
Przykłady
Przykład #1 pg_unescape_bytea() example
<?php
// Connect to the database
$dbconn = pg_connect('dbname=foo');
// Get the bytea data
$res = pg_query("SELECT data FROM gallery WHERE name='Pine trees'");
$raw = pg_fetch_result($res, 'data');
// Convert to binary and send to the browser
header('Content-type: image/jpeg');
echo pg_unescape_bytea($raw);
?>
Rejestr zmian
| Wersja | Opis |
|---|---|
| 5.5.1 | A warning is thrown if the input string is invalid. |
Zobacz też:
- pg_escape_bytea() - Dodaje znaki ucieczki do łańcucha dodającego do pola typu bytea
- pg_escape_string() - Dodaje znaki ucieczki do łańcucha znaków (stringa) używanego w zapytaniach
add a note
User Contributed Notes 3 notes
liviu dot mirea at gmail dot com ¶
13 years ago
muralito at montevideo dot com dot uy ¶
13 years ago
The workaround is to configure a property in the postgres database for the user, to make postgres behave as the old default.
ALTER USER username SET bytea_output = 'escape';
(or using the pgadmin interface)
tiagopastorello at gmail dot com ¶
15 years ago
<?php
$conexao = pg_connect("host=localhost dbname=name user=postgres password=123456") or die('Sorry =( : ' . pg_last_error());
$cod= $_GET['cod'];
$sql = "SELECT * FROM table WHERE cod_field = '$cod'";
$quer = pg_query($conexao, $sql);
$reg = pg_fetch_object($query);
print pg_unescape_bytea($reg -> field_bytea);
?>
