Connect PHP to PolarDB Oracle-Compatible via pg_connect - PolarDB

Connect a PHP client to a PolarDB cluster compatible with Oracle using the pg_connect() function from the pgsql extension.

Prerequisites

A database account is created in the PolarDB cluster. For more information, see Create a database account.
The IP address of the host that you use to access the PolarDB cluster is added to a whitelist. For more information, see Configure a cluster whitelist.

Set up the PHP environment

Choose the setup steps for your operating system.

Windows

Download and install WampServer.
Enable the PostgreSQL plug-in by modifying php.ini: Before:
1. Open php.ini. The file is typically located at C:\wamp\bin\php\php<version>\php.ini, where <version> matches your installed PHP version (for example, php5.6.40).
2. Find the following lines and remove the leading semicolons to uncomment them:
```
;extension=php_pgsql.dll
;extension=php_pdo_pgsql.dll
```
After:
```
extension=php_pgsql.dll
extension=php_pdo_pgsql.dll
```
If the lines do not exist in the file, add them without the semicolons.
Copy libpq.dll from C:\wamp\bin\php\php<version> to C:\windows\system32\.
Restart the Apache service.

Linux

Install the php-pgsql driver:
```
sudo yum install php-pgsql.x86_64
```
Open php.ini:
```
vim /etc/php.ini
```
Add the following line to php.ini:
```
extension=php_pgsql.so
```

Connect to PolarDB

The following script connects to PolarDB, runs a query against pg_roles, and prints the results.

<?php
// Connection parameters — replace with your actual values
$host        = "<cluster-endpoint>";
$port        = "1521";
$dbname      = "<database-name>";
$user        = "<username>";
$password    = "<password>";

// Establish a connection
$db = pg_connect("host=$host port=$port dbname=$dbname user=$user password=$password");

if (!$db) {
    echo "Error: Unable to connect to the database.\n";
    exit(1);
} else {
    echo "Connected successfully.\n";
}

// Run a query
$sql = "SELECT * FROM pg_roles;";
$result = pg_query($db, $sql);

if (!$result) {
    echo pg_last_error($db);
} else {
    echo "Query executed successfully.\n";
    $rows = pg_fetch_all($result);
    print_r($rows);
}

// Close the connection
pg_close($db);
?>

Replace the placeholders with your actual values:

Placeholder	Description	Example
`<cluster-endpoint>`	Endpoint of the PolarDB cluster. See View or apply for an endpoint.	`"host=xxxxxx"`
`<database-name>`	Name of the database to connect to	`"dbname=xxxx"`
`<username>`	Username for the database account	`"user=xxx"`
`<password>`	Password for the database account	—

The default port for PolarDB clusters compatible with Oracle is 1521.

What's next

For a full list of PHP functions for PostgreSQL connections, see the PHP pgsql documentation.