PHP PDO::rollBack() Method: Usage and Examples

Undoes eligible changes in an active transaction.

The objective is to understand the behavior and operational limits, not only the method name.

What It Does

Undoes eligible changes in an active transaction.

Syntax and Return Value

PDO::rollBack(): mixed

The return value and exceptional cases depend on the call described here: Calling it without a transaction throws an exception; DDL may already be committed.

Example 1: Basic Use

This self-contained SQLite example uses in-memory demo data; it requires the pdo_sqlite driver.

<?php
$pdo = new PDO('sqlite::memory:', null, null, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
$pdo->exec('CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT NOT NULL, price INTEGER NOT NULL, active INTEGER)');
$pdo->exec("INSERT INTO products (id,name,price,active) VALUES (1,'Desk',120,1),(2,'Lamp',35,1),(3,'Chair',85,0)");
$pdo->beginTransaction();
$pdo->exec("UPDATE products SET price = 48 WHERE id = 1");
$pdo->rollBack();
echo $pdo->query("SELECT price FROM products WHERE id = 1")->fetchColumn();

Example 2: A Second Scenario

This self-contained SQLite example uses in-memory demo data; it requires the pdo_sqlite driver.

<?php
$pdo = new PDO('sqlite::memory:', null, null, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
$pdo->exec('CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT NOT NULL, price INTEGER NOT NULL, active INTEGER)');
$pdo->exec("INSERT INTO products (id,name,price,active) VALUES (1,'Desk',120,1),(2,'Lamp',35,1),(3,'Chair',85,0)");
$pdo->beginTransaction();
$pdo->exec("UPDATE products SET price = 62 WHERE id = 2");
$pdo->rollBack();
echo $pdo->query("SELECT price FROM products WHERE id = 2")->fetchColumn();

Example 3: Practical Checks

This self-contained SQLite example uses in-memory demo data; it requires the pdo_sqlite driver.

<?php
$pdo = new PDO('sqlite::memory:', null, null, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
$pdo->exec('CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT NOT NULL, price INTEGER NOT NULL, active INTEGER)');
$pdo->exec("INSERT INTO products (id,name,price,active) VALUES (1,'Desk',120,1),(2,'Lamp',35,1),(3,'Chair',85,0)");
$pdo->beginTransaction();
$pdo->exec("UPDATE products SET price = 79 WHERE id = 3");
$pdo->rollBack();
echo $pdo->query("SELECT price FROM products WHERE id = 3")->fetchColumn();

Important Behavior and Edge Cases

Calling it without a transaction throws an exception; DDL may already be committed.

For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Undoes eligible changes in an active transaction.
• Calling it without a transaction throws an exception; DDL may already be committed.
• commit persists eligible changes instead.

Choose this API or pattern when its exact semantics match your task, and verify the result against the database driver and runtime used by your application.