Be aware when you modify a lo with pg_lowrite() to remove first the old one : if the new lo is smaller than the one before, it only overwrite the begining and you keep the end of the old lo (open with "w" parameter, PHP 4.04 Linux RH).
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
pg_lo_write — Escribe un objeto de gran tamaño de PostgreSQL
pg_lo_write() escribe datos dentro de un objeto de gran tamaño en la posición actual.
Para manipular un objeto de gran tamaño (lo), es necesario colocar las operaciones dentro de un bloque de transacción.
Nota:
Anteriormente, esta función se llamaba pg_lowrite().
lobAn PgSql\Lob instance, returned by pg_lo_open().
data
Los datos a ser escritos en el objeto de gran tamaño. Si length es un int y es inferior al tamaño de data, solo los primeros length bytes serán escritos.
length
Un número máximo de bytes a escribir. Debe ser superior a cero y menor al tamaño de data. Este argumento es opcional; si se omite, tomará por defecto el tamaño de data.
El número de bytes escritos en el objeto de gran tamaño o false en caso de error.
| Versión | Descripción |
|---|---|
| 8.1.0 |
The lob parameter expects an PgSql\Lob
instance now; previously, a recurso was expected.
|
| 8.0.0 |
connection es ahora nullable.
|
Ejemplo #1 Ejemplo con pg_lo_write()
<?php
$doc_oid = 189762345;
$data = "Esto sobrescribirá el inicio del objeto de gran tamaño.";
$database = pg_connect("dbname=jacarta");
pg_query($database, "begin");
$handle = pg_lo_open($database, $doc_oid, "w");
$data = pg_lo_write($handle, $data);
pg_query($database, "commit");
?>
Be aware when you modify a lo with pg_lowrite() to remove first the old one : if the new lo is smaller than the one before, it only overwrite the begining and you keep the end of the old lo (open with "w" parameter, PHP 4.04 Linux RH).Using php 4.3.0 and PostgreSQL 7.3.1
I can write a simple script in which pg_lo_write seems to always return 1 and not the number of bytes written, as evidenced by extracting the data through another means.
Further more, I can make this pg_lo_write fail, or at least fail to write all the data it's pretty difficult to tell without the number of bytes written being returned, and not return the false value. In addition to this, the lo resource has been adjusted so that the oid it contains is 0.
Unfortunately, I do not know what exactly the failure mode is, it does seem to be in the ip network communication side of PostgreSQL, which is odd since the unix domain comms works fine for this. However, it would have been useful to have the pg_lo_write() function return as advertised, it would have saved some of the 2 man hours me and the dev. team put into diagnosing this problem.