(PHP 4, PHP 5, PHP 7, PHP 8)
pg_fetch_object — Fetch a row as an object
$result,$row = null,$class = "stdClass",$constructor_args = []pg_fetch_object() returns an object with properties that correspond to the fetched row's field names. It can optionally instantiate an object of a specific class, and pass parameters to that class's constructor.
Note: This function sets NULL fields to the PHP
nullvalue.
Speed-wise, the function is identical to pg_fetch_array(), and almost as fast as pg_fetch_row() (the difference is insignificant).
resultAn PgSql\Result instance, returned by pg_query(), pg_query_params() or pg_execute()(among others).
row
Row number in result to fetch. Rows are numbered from 0 upwards. If
omitted or null, the next row is fetched.
classThe name of the class to instantiate, set the properties of and return. If not specified, a stdClass object is returned.
constructor_args
An optional array of parameters to pass to the constructor
for class objects.
An object with one attribute for each field
name in the result. Database NULL
values are returned as null.
false is returned if row exceeds the number
of rows in the set, there are no more rows, or on any other error.
A ValueError is thrown when
the constructor_args is non-empty with the class not having constructor.
| Version | Description |
|---|---|
| 8.3.0 |
Now throws a ValueError exception when
the constructor_args is non-empty with the class not having constructor;
previously an Exception was thrown.
|
| 8.1.0 |
The result parameter expects an PgSql\Result
instance now; previously, a resource was expected.
|
Example #1 pg_fetch_object() example
<?php
$database = "store";
$db_conn = pg_connect("host=localhost port=5432 dbname=$database");
if (!$db_conn) {
echo "Failed connecting to postgres database $database\n";
exit;
}
$qu = pg_query($db_conn, "SELECT * FROM books ORDER BY author");
while ($data = pg_fetch_object($qu)) {
echo $data->author . " (";
echo $data->year . "): ";
echo $data->title . "<br />";
}
pg_free_result($qu);
pg_close($db_conn);
?>
PostgreSQL boolean true becomes string "t"
PostgreSQL boolean false becomes string "f"
This is ambiguous, and leads to code duplication. I wonder why aren't the types correctly typed when fetching values. We could at least have an optional parameter to enable that.If you're wanting to use objects for your results, but are put off because you can't seem to apply a function to each field of the result (like stripslashes for example), try this code:
<?php
// Code to connect, do query etc etc...
$row = pg_fetch_object($result);
$vars = get_object_vars($row);
foreach ( $vars as $key => $var )
{
$row->{$key} = stripslashes($var);
}
?>I noticed that many people use FOR loops to extract query data. This is the method I use to extract data.
<?php
@$members = pg_query($db_conn, 'SELECT id,name FROM boards.members ORDER BY name;');
if ($members AND pg_num_rows($members)) {
while ($member = pg_fetch_object($members)) {
echo $member->name.' ('.$member->id.')';
}
}
?>
If an error occurs (or nothing is returned) in the above code nothing will output. An ELSE clause can be added to the IF to handle query errors (or nothing being returned). Or a seperate check can be performed for the event that nothing is returned by using an ELSEIF clause.
I like this method because it doesn't use any temporary counter variables.The result_type arg is either invalid or incorrectly documented, since the "result_type is optional..." paragraph is copied verbatim from pg_fetch_array, and the PGSQL_NUM option is in conflict with the preceding paragraph's, "you can only access the data by the field names, and not by their
offsets."When you retrieve the contents of a "timestamp with timezone" field, this will set the environment's timezone variables. Therefore, this is dangerous:
$s=$row->mydatefield;
$unixtimestamp=postgresqltimestamp2unix($s);
echo date("Y-m-d H:i:s",$unixtimestamp);
Here, postgresqltimestamp2unix is a function that converts the postgresql timestamp to Unix. The retrieval of the field data in the first line of the example above will influence the timezone used in date() in the third line.This isn't all that useful. If you do, for example, foreach($row as $field) then you still get every value twice!
You can do something like this, though:
foreach ($line as $key => $cell){
if (! is_numeric($key)){
echo "<td>$key $cell</td>";
}
}
is is_numeric strict enough?Getting db results as object.
<?php
$qry = pg_query("SELECT * FROM users");
$rows = array();
while ($fch = pg_fetch_object($qry)) {
$rows[] = $fch;
}
// or
$rows = array_map(function($a){
return (object) $a;
}, (array) pg_fetch_all($qry));
?>Something I have learned to use:
$result=$pg_query (...);
$num = pg_numrows($result);
for($count=0;$count < $num && $data=pg_fetch_object($result,$count);$count++)
{
printf("<tr>\n");
printf(" <td>%s</td>\n",$data->foo);
printf(" <td>%s</td>\n",$data->bar);
printf("</tr>\n");
}