Abstract: One of the main goals of database systems, relational systems in particular, is to provide a degree of physical data independence for users and programs. Users should not need to know the exact physical storage structures to use the database, and should be protected from changes in those structures. We attempt to go a step further, to logical data independence. We want an interface to a relational database where a user need not be concerned with how the data has been partitioned into various relations. The natural relation schemes to be used, from a semantic point of view, may be decomposed in the database for normalization or redundancy reasons. Our approach essentially loads all the semantics onto the attributes. In our query language tuple variables are not bound to specific relations. Rather, the system uses the set of attributes, say X, that appear in a query with a tuple variable, say t, to combine the database relations to form a single relation with scheme X over which t ranges. We describe our method for constructing such a relation given the associated set of attributes X. When tuple variables are bound implicitly, the logical connectives 'and', 'or', and 'not' take on 'semantic overtones' since they can affect the binding. We discuss the motivation behind the chosen semantics for these connectives. Our goal is a powerful, yet concise, query language with natural semantics.

Abstract: We propose a universal relation scheme database model based on the assumption that there is a unique connection among any set of attributes in a relational database. We use the notion of object ([Sc],[MU]) to give a database designer the ability to control how connections in the database are to be made. We show how semantic considerations that follow naturally from the unique connection assumption constrain how objects and the underlying base relations must be syntactically related. We illustrate and motivate our definitions and constraints with several simple examples.

Abstract: In this paper a method for relational database storage organization is presented.The method is based upon a disaggregation of the relations and a subsequent reaggregation to form the domains on which the relations are defined.A hierarchical organization of the domain is proposed in order to keep track of the relational entities (i.e. relations, tuples and attributes) that insist on the values present in the domains.Then we introduce an implementation technique, referred to as Data Pool, suitable to be processed by a database machine capable of "on the fly" track processing.Finally we present an analytic evaluation of the DP method and an example of database and query with performance comparison of the DP method with the most common flat file technique.The proposed method appears to be generally advantageous in storage occupancy; in data retrieval operations it is extremely effective when joins between permanent relations are performed. Good performances can be achieved with other relational operations using proper parallel architectures and, when temporary relations are involved, using special purpose devices.

Abstract: This paper presents an efficient inter-procedural data flow analysis algorithm for precisely determining aliases in programs that employ a rich set of parameter passing mechanisms and pointer data types. This approach handles the use of pointers bounded to a data type as in Pascal, as well as unbounded pointers that can point to the same locations to which variables map. In the last step of this approach, the alias information is used to compute data flow information that is required for optimization.

Abstract: The problem of characterizing the number of granules (or blocks) accessed by a transaction is important in modeling the performance of database management systems and other applications. Different expressions for this quantity have appeared in the literature under different probabilistic assumptions. These expressions along with one new result are presented with a uniform notation and a clear statement of the assumptions underlying each. The partial order relating the predictions of the expected number of granules accessed is presented.

Abstract: Databases are an important part of many Computer Assisted Design (CAD) applications. Real world knowledge is often defined by a database which is managed by a database system. Unlike most traditional database applications, the CAD process involves significant amounts of scientific and engineering computation on database contents to produce a result. Existing standalone language database systems often cannot meet this computational need. Users can either forego the use of a database system and its conveniences or interface conventional Procedure Oriented Language (POL) programs to database systems for the computational work. This paper describes EXTRAS, a relational algebra query language with extensions for numerical computation. This language has the advantages of a unified approach to computation and database query capabilities and of offering a high level language for numerical computation based on relations.

Abstract: A natural language interface is directed toward the database query languages that access machine stored data. A pattern driven transformation mechanism supports natural language access. A natural language is mapped onto a more formal computer database language. A human-like "understanding" of the query statement is not required. The transformation mechanism is separate from the target database management system. A goal is independence from both domain content and DBMS implementation. There is an emphasis on surface over content analysis.Two particular questions are at issue. First, the extent to which a natural language interface to a database may operate independent of the subject domain of the database. Specifically, the extent to which natural language queries can be evaluated without the use of a query world descriptive reference system. Second, the extent to which natural language queries can be analyzed using pattern recognition techniques.

Abstract: The design of the buffer manager in a Relational Database Management System can significantly affect the overall performance of the system. Thrashing is a common phenomenon that occurs in these systems due to the combination of a regular pattern of accesses made by a process and the competing requests for buffer resources made by concurrently executing processes. In this paper, we present a buffer management algorithm based on a model of database requests. A discussion of problems encountered by traditional methods for buffer management as well as extensions to the algorithm are also presented.

Abstract: It is well known that the growth in demands from end users for new applications is outstripping the capability of data processing departments to implement the corresponding application programs. There are two complementary approaches to attacking this problem (and both approaches are needed): one is to put end users into direct touch with the information stored in computers; the other is to increase the productivity of data processing professionals in the development of application programs. It is less well known that a single technology, relational database management, provides a practical foundation for both approaches. It is explained why this is so.While developing this productivity theme, it is noted that the time has come to draw a very sharp line between relational and nonrelational database systems, so that the label "relational" will not be used in misleading ways. The key to drawing this line is something called a "relational processing capability."

Abstract: Structured query languages, such as those available for relational databases, are becoming increasingly desirable for all database management systems. Such languages are applicative: there is no need for an assignment or update statement. A new technique is described that allows for the implementation of applicative query languages against most commonly used database systems. The technique involves “lazy” evaluation and has a number of advantages over existing methods: it allows queries and functions of arbitrary complexity to be constructed; it reduces the use of secondary storage; it provides a simple control structure through which interfaces to other programs may be constructed; and the implementation, including the database interface, is quite compact. Although the technique is presented for a specific functional programming system and for a CODASYL DBMS, it is general and may be used for other query languages and database systems.