What are the potential pitfalls of manually changing primary key IDs in a database using PHP?

Manually changing primary key IDs in a database using PHP can lead to data inconsistencies and potential errors in related tables that reference the primary key. It is generally not recommended to manually change primary key IDs as it can disrupt the integrity of the database. Instead, consider using auto-increment primary keys or updating related tables when necessary.

// Example of updating a primary key ID in a table with related tables
$old_id = 1;
$new_id = 100;

// Update the primary key ID in the main table
$query = "UPDATE main_table SET id = $new_id WHERE id = $old_id";
$result = mysqli_query($connection, $query);

// Update the foreign key references in related tables
$query = "UPDATE related_table SET main_table_id = $new_id WHERE main_table_id = $old_id";
$result = mysqli_query($connection, $query);