In computer science -- more specifically, in the field of databases -- concurrency control is a method used to ensure that database transactions are executed in a safe manner (i.e., without data loss). Concurrency control is especially applicable to relational databases and database management systems, which must ensure that transactions are executed safely and that they follow the ACID rules. The DBMS must be able to ensure that only serializable, recoverable schedules are allowed, and that no actions of committed transactions are lost while undoing aborted transactions.