pg_result_error
(PHP 4 >= 4.2.0, PHP 5)
pg_result_error — Get error message associated with result
Описание
pg_result_error() returns any error message associated with the result resource. Therefore, the user has a better chance of getting the correct error message than with pg_last_error().
The function pg_result_error_field() can give much greater detail on result errors than pg_result_error().
Because pg_query() returns FALSE if the query fails, you must use pg_send_query() and pg_get_result() to get the result handle.
Список параметров
- result
-
PostgreSQL query result resource, returned by pg_query(), pg_query_params() or pg_execute() (among others).
Возвращаемые значения
Returns a string if there is an error associated with the result parameter, FALSE otherwise.
Примеры
Пример #1 pg_result_error() example
<?php
$dbconn = pg_connect("dbname=publisher") or die("Could not connect");
if (!pg_connection_busy($dbconn)) {
pg_send_query($dbconn, "select * from doesnotexist;");
}
$res1 = pg_get_result($dbconn);
echo pg_result_error($res1);
?>
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Коментарии
Because pg_query() returns FALSE if the query fails, you must must use pg_send_query() and pg_get_result() to get the result handle.
PostgreSQL 7.4 introduced a new function called PQresultErrorField() that can be used to get SQLSTATE code from a query, which is far more useful than the error string returned from pg_result_error().
http://www.postgresql.org/docs/7.4/static/libpq-exec.html
http://www.postgresql.org/docs/7.4/static/errcodes-appendix.html
Here's a patch that adds the pg_result_error_field() function to PHP:
http://collapsed.net/patches/php-4.3.5RC3-pg_result_error_field.diff
(To apply the patch cd into your php-4.3.5RC directory and type: patch -p1 </path/to/php-4.3.5RC3-pg_result_error_field.diff)
Example code:
<?php
if(!($db = pg_connect("user=foo password=bar dbname=foobar")))
die("pg_connect");
if(!pg_send_query($db, "SELECT foo FROM bar"))
die("pg_send_query");
if(!($result = pg_get_result($db)))
die("pg_get_result");
echo(pg_result_error($result) . "<br />\n");
/* only available if you have patched php */
if(function_exists("pg_result_error_field"))
{
$fieldcode = array(
"PGSQL_DIAG_SEVERITY", "PGSQL_DIAG_SQLSTATE",
"PGSQL_DIAG_MESSAGE_PRIMARY", "PGSQL_DIAG_MESSAGE_DETAIL",
"PGSQL_DIAG_MESSAGE_HINT", "PGSQL_DIAG_STATEMENT_POSITION",
"PGSQL_DIAG_CONTEXT", "PGSQL_DIAG_SOURCE_FILE",
"PGSQL_DIAG_SOURCE_LINE", "PGSQL_DIAG_SOURCE_FUNCTION");
foreach($fieldcode as $fcode)
{
printf("%s: %s<br />\n",
$fcode,
pg_result_error_field($result, constant($fcode)));
}
pg_free_result($result);
}
?>
<?php pg_result_error_field($result, PGSQL_DIAG_SQLSTATE); ?>
Returns the SQLSTATE code.
You can use pg_set_error_verbosity() to retrieve SQLSTATUS from pg_last_error().pg_result_error does NOT work with prepared statements.So considering pg_query and pg_query_params don't return results on error, and that this would be an extremely handy thing to have, I just ended up writing my own functions wrapping the pg_send_* ones to work like the aforementionned two <em>should</em>. There's not a whole lot of code to them, the comments are mostly references from the libPQ and PHP doc, to explain the behavior.
<?php
class PostgresConnectionError extends Exception {
public function __construct($last_error) {
parent::__construct($message);
}
}
function pg_send_query_sync($connection, string $query) {
// This function cannot work if any query is already running for that connection because the results may then get mixed up.
assert(pg_get_result($connection) === false);
$dispatch_ok = pg_send_query($connection, $query);
// The *only* case where nothing can be returned, when the connection fails to dispatch the initial query.
if (!$dispatch_ok) throw new PostgresConnectionError(pg_last_error($connection));
// From the libPQ doc : "PQgetResult must be called repeatedly until it returns a null pointer, indicating that the command is done."
// In the case of pg_query/PQExec, which we're trying to emulate:
// "Note however that the returned PGresult structure describes only the result of the last command executed from the string."
// "Should one of the commands fail, processing of the string stops with it and the returned PGresult describes the error condition."
while ($result = pg_get_result($connection)) {
// Drain all results on the connection and only return the last one.
if ($last_result) pg_free_result($last_result);
$last_result = $result;
}
assert(is_resource($result) && get_resource_type($result) === "pgsql result");
return $last_result;
}
function pg_send_query_params_sync($connection, string $query, array $params) {
// This function cannot work if any query is already running for that connection because the results may then get mixed up.
assert(pg_get_result($connection) === false);
$dispatch_ok = pg_send_query_params($connection, $query, $params);
// The *only* case where nothing can be returned, when the connection fails to dispatch the initial query.
if (!$dispatch_ok) throw new PostgresConnectionError(pg_last_error($connection));
// From the libPQ doc : "PQgetResult must be called repeatedly until it returns a null pointer, indicating that the command is done."
// In the case of pg_query_params/PQExecParams, which we're trying to emulate:
// "Unlike PQexec, PQexecParams allows at most one SQL command in the given string. (There can be semicolons in it, but not more than one nonempty command.)"
while ($result = pg_get_result($connection)) {
// Drain all results on the connection, although there should only be one.
if ($last_result) pg_free_result($last_result);
$last_result = $result;
}
assert(is_resource($result) && get_resource_type($result) === "pgsql result");
return $last_result;
}