PDO Last Id - PHP

PDO Last Id is a useful feature in PHP's PDO module that allows you to retrieve the last inserted ID from a database table. This can be handy when you need to retrieve the primary key value of a newly inserted record in your database.

How to Use PDO Last Id in PHP

You can use the lastInsertId() method of the PDO object to get the last inserted ID. Here is an example:

<?php
// connect to database
$pdo = new PDO("mysql:host=localhost;dbname=my_db", "username", "password");

// insert a record
$stmt = $pdo->prepare("INSERT INTO my_table (field1, field2) VALUES (:field1, :field2)");
$stmt->execute(array(":field1" => "value1", ":field2" => "value2"));

// get the last inserted ID
$last_id = $pdo->lastInsertId();

echo "The last inserted ID is $last_id";
?>

Using Last Insert ID in a Transaction

If you are inserting data in a transaction, make sure to call lastInsertId() after committing the transaction. Here's an example:

<?php
// connect to database
$pdo = new PDO("mysql:host=localhost;dbname=my_db", "username", "password");

// start a transaction
$pdo->beginTransaction();

// insert a record
$stmt = $pdo->prepare("INSERT INTO my_table (field1, field2) VALUES (:field1, :field2)");
$stmt->execute(array(":field1" => "value1", ":field2" => "value2"));

// commit transaction
$pdo->commit();

// get the last inserted ID
$last_id = $pdo->lastInsertId();

echo "The last inserted ID is $last_id";
?>

Using Last Insert ID with Multiple Tables

If you need to get the last inserted ID of a different table than the one that you just inserted data to, you can specify the table name as an argument to the lastInsertId() method. Here's an example:

<?php
// connect to database
$pdo = new PDO("mysql:host=localhost;dbname=my_db", "username", "password");

// insert a record
$stmt = $pdo->prepare("INSERT INTO my_table (field1, field2) VALUES (:field1, :field2)");
$stmt->execute(array(":field1" => "value1", ":field2" => "value2"));

// get the last inserted ID from another table
$last_id = $pdo->lastInsertId("another_table");

echo "The last inserted ID from another table is $last_id";
?>

Conclusion

PDO Last Id is a powerful feature in PHP that allows you to retrieve the last inserted ID from a database table. This can be useful when you need to retrieve the primary key value of a newly inserted record. Remember to call lastInsertId() after committing transactions and specify the table name as an argument if you need to get the last inserted ID from a different table.