The NDB API is an object-oriented application programming interface for MySQL Cluster that implements indexes, scans, transactions, and event handling. NDB transactions are ACID-compliant in that they provide a means to group together operations in such a way that they succeed (commit) or fail as a unit (rollback). It is also possible to perform operations in a "no-commit" or deferred mode, to be committed at a later time.

NDB scans are conceptually rather similar to the SQL cursors implemented in MySQL 5.0 and other common enterprise-level database management systems. These allow for high-speed row processing for record retrieval purposes. (MySQL Cluster naturally supports set processing just as does MySQL in its non-Cluster distributions. This can be accomplished via the usual MySQL APIs discussed in the MySQL Manual and elsewhere.) The NDB API supports both table scans and row scans; the latter can be performed using either unique or ordered indexes. Event detection and handling is discussed in Section 2.3.11, “The NdbEventOperation Class”, as well as Section 2.4.7, “NDB API Event Handling Example”.

In addition, the NDB API provides object-oriented error-handling facilities in order to provide a means of recovering gracefully from failed operations and other problems. See Section 2.4.3, “Handling Errors and Retrying Transactions”, for a detailed example.

The NDB API provides a number of classes implementing the functionality described above. The most important of these include the Ndb, Ndb_cluster_connection, NdbTransaction, and NdbOperation classes. These model (respectively) database connections, cluster connections, transactions, and operations. These classes and their subclasses are listed in Section 2.3, “NDB API Classes, Interfaces, and Structures”. Error conditions in the NDB API are handled using NdbError, a structure which is described in Section 2.3.31, “The NdbError Structure”.