A database system and a computer implemented method for managing functions in the database system is provided. The method, implemented using instructions that may be stored in the database system, involves obtaining first data representing a set of one or more operations to be performed on data in the database system. Second data, representing a function definition, is derived from the first data and the function definition includes the set of one or more operations and a set of state variables. A function is generated according to the second data. Generating the function includes storing a set of one or more values for respective ones of the state variables. The set of values are stored in an isolated computing environment in the database system and the function is configured to operate on the values in the isolated computing environment.