How does CodeIgniter ensure data integrity during transactions?

CodeIgniter ensures data integrity during transactions by employing foreign key constraints. Foreign key constraints establish a relationship between tables, ensuring that the values in a column (or columns) of one table match the values in another table's primary key. When a transaction involves multiple tables with foreign key relationships, CodeIgniter ensures that the foreign key constraints are satisfied, maintaining the consistency and integrity of the data across tables. Foreign key constraints prevent actions that would compromise the referential integrity of the database.