PostgreSQL PHP: Calling Stored Procedures

Summary: in this tutorial, you will learn how to call stored procedures in PostgreSQL in PHP using PDO.

Calling a stored procedure that returns one value

Let’s create a simple stored procedure named add() that returns the product of two integers using plpgsql.

CREATE OR REPLACE FUNCTION add(
    a INTEGER,
    b INTEGER)
  RETURNS integer AS $$
BEGIN
return a + b;
END; $$
  LANGUAGE 'plpgsql';Code language: SQL (Structured Query Language) (sql)

To call a stored procedure that returns one value, you use these steps:

1. Connect to the PostgreSQL database server by creating a new instance of the PDO class.
2. Prepare the statement that calls the stored procedure for execution using the prepare() method of the PDO object. The prepare() method returns a PDOStatement object.
3. Optionally pass values to the statement using the bindValue() method.
4. Execute the statement using the execute() method of the PDOStatement object. You can pass the values to the statement when calling the execute() method as well.
5. Get the value using the fetchColumn() method that returns a single column of the next row in the result set.

The following add() method demonstrates how to call the add() stored procedure in PostgreSQL database.

   /**
     * Call a simple stored procedure
     * @param int $a
     * @param int $b
     * @return int
     */
    public function add($a, $b) {
        $stmt = $this->pdo->prepare('SELECT * FROM add(:a,:b)');
        $stmt->setFetchMode(\PDO::FETCH_ASSOC);
        $stmt->execute([
            ':a' => $a,
            ':b' => $b
        ]);
        return $stmt->fetchColumn(0);
    }Code language: PHP (php)

To test the add() method, you use the following code in the index.php file:

<?php

require 'vendor/autoload.php';

use PostgreSQLTutorial\Connection as Connection;
use PostgreSQLTutorial\StoreProc as StoreProc;

try {
    // connect to the PostgreSQL database
    $pdo = Connection::get()->connect();
    // 
    $storeProc = new StoreProc($pdo);

    $result = $storeProc->add(20, 30);
    echo $result;
    
} catch (\PDOException $e) {
    echo $e->getMessage();
}Code language: PHP (php)

Calling a stored procedure that returns a result set

We will use the accounts, plans, and account_plans tables for the sake of demonstration. The following get_accounts() stored procedure returns a result set that contains complete data of accounts.

CREATE OR REPLACE FUNCTION get_accounts()
  RETURNS TABLE(id integer, 
                first_name character varying, 
                last_name character varying, 
                plan character varying, 
                effective_date date) AS
$$
BEGIN
 RETURN QUERY 

 SELECT a.id,a.first_name,a.last_name, p.plan, ap.effective_date
 FROM accounts a
 INNER JOIN account_plans ap on a.id = account_id
 INNER JOIN plans p on p.id = plan_id
 ORDER BY a.id, ap.effective_date;
END; $$

LANGUAGE plpgsql;Code language: SQL (Structured Query Language) (sql)

The steps of calling a stored procedure that returns a result set are the same as the steps of querying data.

The following getAccounts() method demonstrates how to call the get_accounts() stored procedure in PHP.

   /**
     * Call a stored procedure that returns a result set
     * @return array
     */
    function getAccounts() {
        $stmt = $this->pdo->query('SELECT * FROM get_accounts()');
        $accounts = [];
        while ($row = $stmt->fetch()) {
            $accounts[] = [
                'id' => $row['id'],
                'first_name' => $row['first_name'],
                'last_name' => $row['last_name'],
                'plan' => $row['plan'],
                'effective_date' => $row['effective_date']
            ];
        }
        return $accounts;
    }Code language: PHP (php)

To test the getAccounts() method, you use the following code in the account.php file.

<?php
require 'vendor/autoload.php';

use PostgreSQLTutorial\Connection as Connection;
use PostgreSQLTutorial\StoreProc as StoreProc;

try {
    // connect to the PostgreSQL database
    $pdo = Connection::get()->connect();
    // 
    $storeProc = new StoreProc($pdo);
   
    $accounts = $storeProc->getAccounts();
    
} catch (\PDOException $e) {
    echo $e->getMessage();
}
?>
<!DOCTYPE html>
<html>
    <head>
        <title>PostgreSQL PHP: calling stored procedure demo</title>
        <link rel="stylesheet" href="https://cdn.rawgit.com/twbs/bootstrap/v4-dev/dist/css/bootstrap.css">
    </head>
    <body>
        <div class="container">
            <h1>Account List</h1>
            <table class="table table-bordered">
                <thead>
                    <tr>
                        <th>ID</th>
                        <th>First Name</th>
                        <th>Last Name</th>
                        <th>Plan</th>
                        <th>Effective Date</th>
                    </tr>
                </thead>
                <tbody>
                    <?php foreach ($accounts as $account) : ?>
                        <tr>
                            <td><?php echo htmlspecialchars($account['id']) ?></td>
                            <td><?php echo htmlspecialchars($account['first_name']); ?></td>
                            <td><?php echo htmlspecialchars($account['last_name']); ?></td>
                            <td><?php echo htmlspecialchars($account['plan']); ?></td>
                            <td><?php echo htmlspecialchars($account['effective_date']); ?></td>
                        </tr>
                    <?php endforeach; ?>
                </tbody>
            </table>
        </div>
    </body>
</html>Code language: SQL (Structured Query Language) (sql)

In this tutorial, we have shown you how to call stored procedures from PostgreSQL using PHP PDO.