A transactional database is a type of database designed to handle a large number of transactions efficiently. These databases ensure that all operations are completed successfully or not at all, maintaining data integrity. This is often achieved through the use of the ACID properties: Atomicity, Consistency, Isolation, and Durability. Transactional databases are commonly used in applications like banking systems, where accurate and reliable data processing is crucial. They support operations such as inserting, updating, and deleting records while ensuring that concurrent transactions do not interfere with each other, thus providing a stable environment for data management.