E. F. Codd

A data base sublanguage founded on the relational calculus

Three principal types of language for data base manipulation are identified: the low-level, procedure-oriented (typified by the CODASYL-proposed DML), the intermediate level, algebraic (typified by the Project MAC MacAIMS language), and the high level, relational calculus-based data sublanguage, an example of which is described in this paper. The language description is informal and stresses concepts and principles. Following this, arguments are presented for the superiority of the calculus-based type of data base sub-language over the algebraic, and for the algebraic over the low-level procedural. These arguments are particularly relevant to the questions of inter-system compatibility and standardization.

Relational database: a practical foundation for productivity

Publisher Summary This chapter discusses a series of arguments to support the claim that relational database technology offers dramatic improvements in productivity both for end users and for application programers. The arguments center on the data independence, structural simplicity, and relational processing defined in the relational model and implemented in relational database management systems. All three of these features simplify the task of developing application programs and the formulation of queries and updates to be submitted from a terminal. In addition, the first feature tends to keep programs viable in the face of organizational and descriptive changes in the database and, therefore, reduces the effort that is normally diverted into the maintenance of programs. The relational database provides only a foundation for improved productivity and not the total solution. The reason is simple: relational database deals only with the shared data component of application programs and end-user interactions.

Normalized data base structure: a brief tutorial

Casual and other users of large formatted data bases need a simple tabular (relational) view of the data rather than a network or tree-structured view. This paper illustrates the removal of repeating groups, hierarchic and plex structures, and cross-referencing structures. Finally, the simplification of data base relations by normalization is discussed.

Multiprogram scheduling: parts 1 and 2. introduction and theory

In order to exploit fully a fast computer which possesses simultaneous processing abilities, it should to a large extent schedule its own workload. The scheduling routine must be capable of extremely rapid execution if it is not to prove self-defeating. The construction of a schedule entails determining which programs are to be run concurrently and which sequentially with respect to each other. A concise scheduling algorithm is described which tends to minimize the time for executing the entire pending workload (or any subset of it), subject to external constraints such as precedence, urgency, etc. The algorithm is applicable to a wide class of machines.

OLAP On-Line Analytical Processing

Im Bereich der Informationstechnologie besteht ein vielfaltiger Bedarfan Hilfen zum Analysieren und Bearbeiten von numerischen und verschiedenen anderen Informationsmengen. Dabei werden insbesondere solche Instrumente benotigt, die die Fahigkeit haben, auf viele unterschiedliche Datentypen zuzugreifen, mehrdimensionale Perspektiven der Daten zu erzeugen, mit verschiedenen Datenformaten und Datenaggregationen zu experimentieren, neue Informationsmodelle zu definieren und darzustellen, die Modelle zusammenzufassen, zu konsolidieren, zu summieren und Formeln auf sie anzuwenden, durch Konsolidierungspfade auf und ab zu navigieren, sie aufzuteilen und zu zerlegen, zu drehen und zu rotieren, eine Vielfalt von Berichten zu generieren, die die einzelnen Arbeitsschritte widerspiegeln.

Data models in database management

It is a combination of three components: 1) a collection of data structure types (the building blocks of any database that conforms to the model); 2) a collection of operators or inferencing rules, which can be applied to any valid instances of the data types listed in (1), to retrieve or derive data from any parts of those structures in any combinations desired; 3) a collection of general integrity rules, which implicitly or explicitly define the set of consistent database states or changes of state or both—these rules may sometimes be expressed as insert-update-delete rules.

Natural language interfaces

The panel will focus on the different approaches to creating natural language interfaces to DBMS. Of particular interest is the manner in which database definition information, user feedback dialogues, storage of the lexicon and database path selection are handled. The panelists have all been involved in implementing such interfaces.