正如手册所说，你应该尝试一下。如下所示。
http://php.net/manual/en/function.pg-connect.php
$dbconn = pg_connect("host=e5-31-281-414-28.compute-1.amazonaws.com port=5432 dbname=b6m44bwjmaa41n user=sgjwiakskki password=e4ks28ajgs87");
说明
资源 pg_connect ( string $connection_string [, int
$connect_type ])
connection_string 可以为空以使用所有默认参数，或者
它可以包含一个或多个以空格分隔的参数设置。
每个参数设置的形式为keyword = value。周围空间
等号是可选的。写入空值或值
包含空格，用单引号括起来，例如，keyword = 'a
价值'。值中的单引号和反斜杠必须转义
带有反斜杠，即 \' 和 \.
更新：
我没有 php。所以，我刚刚从旧的 ubuntu 存储库安装了 php5.6 和 php5.6-pqsql 包（我使用的是 Linux Mint 18.1，32 位）
$ date
Tue Dec 27 00:49:11 +04 2016
$ grep install /var/log/dpkg.log
2016-12-27 00:05:11 install php-common:all <none> 1:47+deb.sury.org~xenial+1
...
2016-12-27 00:05:22 install php5.6:all <none> 5.6.29-1+deb.sury.org~xenial+1
...
2016-12-27 00:22:26 status installed php5.6-pgsql:i386 5.6.29-1+deb.sury.org~xenial+1
...
然后在 heroku 上创建帐户。设置一个数据库，我正在添加连接凭据（因为我不需要它）。
Host
ec2-54-217-212-8.eu-west-1.compute.amazonaws.com
Database
d464heusrdn2k5
User
mgtvhefjhzilai
Port
5432
Password
fd6aa97d31b25c26a41a8211008f1838abd76d7715dcac7c742bfc55f37bd50f
以上给出，
$ php -v
PHP 5.6.29-1+deb.sury.org~xenial+1 (cli)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
$ php -a
Interactive mode enabled
php > $dbconn = pg_connect("host=ec2-54-217-212-8.eu-west-1.compute.amazonaws.com port=5432 dbname=d464heusrdn2k5 user=mgtvhefjhzilai password=fd6aa97d31b25c26a41a8211008f1838abd76d7715dcac7c742bfc55f37bd50f");
php > $sql = "create table lorem (id int not null, foo varchar(15), primary key (id));";
php > $r = pg_query($dbconn, $sql);
php > $tbls = "select * from information_schema.tables";
php > $qr = pg_query($dbconn, $tbls);
php > while($r = pg_fetch_array($qr)) {
php { print_r($r);
php { }
Array
(
[0] => d464heusrdn2k5
[table_catalog] => d464heusrdn2k5
[1] => public
[table_schema] => public
[2] => lorem
[table_name] => lorem
[3] => BASE TABLE
[table_type] => BASE TABLE
[4] =>
[self_referencing_column_name] =>
[5] =>
[reference_generation] =>
[6] =>
[user_defined_type_catalog] =>
[7] =>
[user_defined_type_schema] =>
[8] =>
[user_defined_type_name] =>
[9] => YES
[is_insertable_into] => YES
[10] => NO
[is_typed] => NO
[11] =>
[commit_action] =>
)
Array