PostgreSQL PHP: Updating Data In a Table

Summary: in this tutorial, you will learn to update data in a PostgreSQL database table using PHP PDO.

Steps for updating data in a database table from a PHP application

To update data in a table, you use these steps:

1. Connect to the PostgreSQL database server by creating an instance of the PDO class.
2. Call the prepare() method of the PDO object to prepare the UPDATE statement for execution. The prepare() method returns a PDOStatement object.
3. Pass the values to the UPDATE statement by calling the bindValue() method of the PDOStatement object.
4. Execute the UPDATE statement by calling the execute() method of the PDOStatement object.
5. Get the number of rows updated using the rowCount() method of the PDOStatement object.

Updating data example

We will use the stocks table that we created in the creating table tutorial for the demonstration.

The updateStock() method of the PostgreSQLPHPUpdate class updates the data in the stocks table based on a specified id.

<?php

namespace PostgreSQLTutorial;

/**
 * PostgreSQL PHP Update Demo
 */
class PostgreSQLPHPUpdate {

    /**
     * PDO object
     * @var \PDO
     */
    private $pdo;

    /**
     * Initialize the object with a specified PDO object
     * @param \PDO $pdo
     */
    public function __construct($pdo) {
        $this->pdo = $pdo;
    }

    /**
     * Update stock based on the specified id
     * @param int $id
     * @param string $symbol
     * @param string $company
     * @return int
     */
    public function updateStock($id, $symbol, $company) {

        // sql statement to update a row in the stock table
        $sql = 'UPDATE stocks '
                . 'SET company = :company, '
                . 'symbol = :symbol '
                . 'WHERE id = :id';

        $stmt = $this->pdo->prepare($sql);

        // bind values to the statement
        $stmt->bindValue(':symbol', $symbol);
        $stmt->bindValue(':company', $company);
        $stmt->bindValue(':id', $id);
        // update data in the database
        $stmt->execute();

        // return the number of row affected
        return $stmt->rowCount();
    }
}Code language: PHP (php)

We use the PostgreSQLPHPUpdate class in the index.php file as follows:

<?php

require 'vendor/autoload.php';

use PostgreSQLTutorial\Connection as Connection;
use PostgreSQLTutorial\PostgreSQLPHPUpdate as PostgreSQLPHPUpdate;

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

    // 
    $updateDemo = new PostgreSQLPHPUpdate($pdo);

    // insert a stock into the stocks table
    $affectedRows = $updateDemo->updateStock(2, 'GOOGL', 'Alphabet Inc.');

    echo 'Number of row affected ' . $affectedRows;
} catch (\PDOException $e) {
    echo $e->getMessage();
}Code language: PHP (php)

In the index.php script, we connected to the PostgreSQL database and called the updateStock() method of the PostgreSQLPHPUpdate class to update the company name of the stock id 2 from Google Inc. to Alphabet Inc.

Before running the script, we query data from the stocks table to see its current data.

SELECT 
    id, symbol, company
FROM
    stocks;Code language: SQL (Structured Query Language) (sql)

 id | symbol |        company
----+--------+-----------------------
  1 | MSFT   | Microsoft Corporation
  2 | GOOG   | Google Inc.
  3 | YHOO   | Yahoo! Inc.
  4 | FB     | Facebook, Inc.
(4 rows)

Launch the index.php file in a web browser; we get the following output.

Number of row affected 1Code language: JavaScript (javascript)

Let’s recheck the stocks table.

 id | symbol |        company
----+--------+-----------------------
  1 | MSFT   | Microsoft Corporation
  2 | GOOGL  | Alphabet Inc.
  3 | YHOO   | Yahoo! Inc.
  4 | FB     | Facebook, Inc.
(4 rows)Code language: SQL (Structured Query Language) (sql)

The company name of stock with id 2 has been updated to the new one.

In this tutorial, you have learned how to update data in a PostgreSQL table using the prepared statement in PHP PDO.