1. A database system comprising: a processor to execute computer program instructions; a memory to store computer program instructions executable by the processor and data to be processed by the processor; computer program instructions stored in the memory; and data stored in the memory; wherein, the computer program instructions and the data implement: a plurality of datasets, each dataset including a plurality of data; and a plurality of database objects, each object having a security label comprising a security classification of the object, wherein a security label of at least one database object is determined by assigning a security label of a user of the database system with which the database session is associated as an initial security label, then determining a maximum session label based on application of a merge label format to each of a plurality of additional security factors using a selected one of a plurality of stored merging functions; at least one database session, the database session having a security label indicating a security classification of the database session; wherein, the database system is operable to allow or deny access to data to a database session based on a security label of a database object and on a security label of the database session.