PHP PDO API Reference

`PDO`

7 methods

Represents a connection between PHP and a database server, providing prepared statements and transactions.

PDO::__construct(string $dsn, ?string $username = null, ?string $password = null, ?array $options = null)

Creates a PDO instance representing a connection to a database via DSN.

Parameters

Name	Type	Description
dsn	string	Data Source Name (e.g. 'mysql:host=localhost;dbname=test').
username	?string	Database username.
password	?string	Database password.
options	?array	Driver-specific options.

Returns

void

Example

php

<?php
$pdo = new PDO(
    "mysql:host=localhost;dbname=test;charset=utf8mb4",
    "root",
    "secret",
    [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]
);

PDO::query(string $query, ?int $fetchMode = null): PDOStatement|false

Executes an SQL statement, returning a result set as a PDOStatement. Use for non-parameterized queries.

Parameters

Name	Type	Description
query	string	SQL statement to execute.
fetchMode	?int	Optional fetch mode.

Returns

PDOStatement|false

Example

php

<?php
$stmt = $pdo->query("SELECT id, name FROM users");
foreach ($stmt as $row) {
    echo $row["name"];
}

PDO::prepare(string $query, array $options = []): PDOStatement|false

Prepares a statement for execution and returns a PDOStatement object. Use for parameterized queries.

Parameters

Name	Type	Description
query	string	SQL statement with placeholders.
options	array	Driver options.

Returns

PDOStatement|false

Example

php

<?php
$stmt = $pdo->prepare("SELECT * FROM users WHERE id = :id");
$stmt->execute([":id" => 42]);
$user = $stmt->fetch();

PDO::beginTransaction(): bool

Turns off autocommit mode and begins a transaction. Changes are not committed until commit().

Returns

bool

Example

php

<?php
$pdo->beginTransaction();
try {
    $pdo->exec("UPDATE accounts SET bal = bal - 100 WHERE id = 1");
    $pdo->exec("UPDATE accounts SET bal = bal + 100 WHERE id = 2");
    $pdo->commit();
} catch (Exception $e) {
    $pdo->rollBack();
}

PDO::commit(): bool

Commits a transaction, making all changes since beginTransaction() permanent.

Returns

bool

Example

php

<?php
$pdo->beginTransaction();
$pdo->exec("INSERT INTO logs (msg) VALUES ('hi')");
$pdo->commit();

PDO::rollBack(): bool

Rolls back the current transaction, undoing all changes made since beginTransaction().

Returns

bool

Example

php

<?php
$pdo->beginTransaction();
$pdo->exec("DELETE FROM users WHERE id = 1");
$pdo->rollBack();  // DELETE is undone

PDO::lastInsertId(?string $name = null): string|false

Returns the ID of the last inserted row, or the last value from a sequence.

Parameters

Name	Type	Description
name	?string	Sequence name (some drivers like PostgreSQL).

Returns

string|false

Example

php

<?php
$pdo->exec("INSERT INTO users (name) VALUES ('Ann')");
$id = $pdo->lastInsertId();
echo $id;  // e.g. "42"

All references Next: string functions