This thesis discusses the design and implementation of a relational database programming language, focusing on the domain algebra for nested relations. While the relational algebra provides operations to manipulate relations as data primitives, the domain algebra allows the manipulation of the attributes of relations. With the nested relational model, the domain algebra subsumes the functionality of the relational algebra. The conventional relational operations (e.g. selection and projection) may be applied to the attributes of a relation.;The domain algebra for nested relations has many advantages. For example, the domain algebra makes the nesting and unnesting of relations very easy. This ensures that any hierarchical database schema can be validly translated into a conventional 1NF database schema. With the nested domain algebra, defining abstract data types for domains can be achieved as well.;The system consists of three modules; the relational algebra, the domain algebra and computations. This thesis deals with the domain algebra module.;The implementation is part of the jRelix project at McGill University. The most significant feature of jRelix is the support for the nested relations with an arbitrary but finite level of nesting. The Object-Oriented programming language Java was used exclusively during the implementation, which secures jRelix as a platform independent database programming language.
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