The authors present a common foundation for integrating pairs of entity sets, pairs of relationship sets, and an entity set with a relationship set. This common foundation is based on the basic principle of integrating attributes. Any pair of objects whose identifying attributes can be integrated can themselves be integrated. Several definitions of attribute equivalence are presented. These definitions can be used to specify the exact nature of the relationship between a pair of attributes. Based on these definitions, several strategies for attribute integration are presented and evaluated.>

An interactive tool has been developed to assist database designers and administrators (DDA) in integrating schemas. It collects the information required for integration from a DDA, performs essential bookkeeping, and integrates schemas according to the semantics provided. The authors present the capabilities of this tool by discussing the integration methodology and the user interface of the tool.>

DDTS (Distributed Database Testbed System) was developed for the purpose of evaluating alternative approaches and algorithms for managing data stored in several databases on different machines. An overview of the system and information architectures of DDTS, as well as an example of the execution of a distributed request, are presented. The results of experiments with three query optimization algorithms are summerized. Our approach for dealing with semantic integrity constraints in a distributed system is reviewed. By sacrificing the enforcement of semantic integrity constraints that span sites, DDTS can be used as a federated distributed database management system.

Users can formulate database requests by constructing a pictorial pattern on a video display screen. Patterns may be constructed by entering conditions into electronic form templates and also by combining other patterns. Patterns form the basis of a language for database access. Requirements of language for office workers to access a database are outlined. We present a formal description of the Forms Pattern Language and illustrate how this language can be used to interactively formulate database requests and browse through the database contents. The Forms Pattern Language is evaluated with respect to the language requirements of office workers. A linear. keyword-oriented version and a pictorial version of the Forms Pattern Language are also presented.

Existing computer systems frequently provide two I/O systems: a (language) file system and a data base management system. Generally, 'little interaction between the systems is available to applications, in the sense that data accessed through one cannot be accessed through the other. We explore three methods of combining the systems: adding file access to an existing data base, adding data base access to an existing file, and completely integrating file management and data base management into a single data management system. Motivations for all three methods are supplied. Implications for existing or newly designed software components are explored.