pg_fetch_object()

(PHP 4, PHP 5, PHP 7)

提取一行作为对象

说明

pg_fetch_object(resource $result[,int $row[,int $result_type]]): object

pg_fetch_object()返回与所提取行的属性相一致的一个对象。如果出错或者没有更多行可供提取时则返回FALSE。

pg_fetch_object()和pg_fetch_array()相似，只有一点区别－返回一个对象而不是数组。间接的，这意味着只能通过字段名来访问数据而不能通过偏移量来访问（数字是非法的属性名）。

$row是想要取得的行（记录）的编号。第一行为 0。

除了速度之外，本函数和pg_fetch_array()完全一样，而且几乎和pg_fetch_row()一样快（速度上的差别很小）。

Note:

从 4.1.0 版本开始，参数$row变为可选参数。

从 4.3.0 开始，$result_type默认值为 PGSQL_ASSOC，而旧版本的默认值是 PGSQL_BOTH。数字属性在这里没有用处，因为在 PHP 中对象的属性不能是数字。

$result_type参数在以后的版本中可能会删除。

Example #1 pg_fetch_object()

<?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");
$row = 0; // postgres needs a row counter 
while ($data = pg_fetch_object($qu, $row)) {
    echo $data->author . " (";
    echo $data->year . "): ";
    echo $data->title . "<br />";
    $row++;
}
pg_free_result ($qu);
pg_close ($db_conn);
?>

Note:

从 4.1.0 开始，$row成为可选参数。每次调用pg_fetch_object()，内部的行计数器都会加一。

参见pg_query()，pg_fetch_array()，pg_fetch_row()和pg_fetch_result()。

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.

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));
?>

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.

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."

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?

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");
}