Bulk Types and Iterators: Introduction and State of the Art

A bulk type describes a homogeneous collection of values. These values are described by another type which is given as a parameter to the bulk type constructor. Many bulk types such as sets, lists and relations are already familiar and widely used in data-intensive applications. Additional bulk types, like bags and multisets, can be defined either by system providers or by expert users. Languages with multiple bulk types have a higher potential for problem-oriented data modelling. In particular, by using bulk types to describe data that resides in legacy databases one gains access to that data in a convenient, consistent and safe manner.