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A data definition language is a declarative computer language for specifying data structures. Most data definition languages concentrate on the declaration of logical data structures with little concern for how these structures are physically realized on a computer system. However, the need for data definition languages which describe both the logical and physical aspects of data is increasingly apparent. Such languages will be a key element in the translation of data between computer systems, as well as in advanced data management systems and distributed data bases. This paper reviews past work in the data definition language for describing both logical and physical aspects of data. Applications of these "generalized" data definition languages are also discussed. [ABSTRACT FROM AUTHOR]

In certain data base organization schemes the cost per access may increase due to structural inefficiencies caused by updates. By reorganizing the data base the cost per access may be reduced. However, the high cost of a reorganization prohibits frequent reorganizations. This paper examines strategies for selecting the optimum reorganization points. [ABSTRACT FROM AUTHOR]

The article reports on the growth of information service companies that store reams of data on film. The U.S. industry's need for information, coupled with advanced technologies, have helped establish the new business of the microimage or microform, data bank. Among the advantages of the microform are easy storage and access to information and low-cost reproduction. The companies that are actively involved in the sector include Bell & Howell and McGraw-Hill, Inc.

A calendar of events sponsored by the Association for Computing Machinery (ACM) or a subunit of ACM is presented. The National Operations and Automation Conference will be held in Washington D.C. The Australian Computer Conference will be sponsored by the Australian Computer Society. The Conference on Large Data Bases will also be held in Washington D.C.

It is proposed that the data base management function be placed on a dedicated back-end computer which accepts commands (in a relatively high level language such as the CODASYL Data Base Task Group, April 1971 Report) from a host computer, accesses the data base on secondary storage, and returns results. The advantages of such a configuration are discussed An experimental implementation, called the experimental Data Management System, XDMS, is described and certain conclusions about the back-end approach are drawn from this implementation. [ABSTRACT FROM AUTHOR]

Focuses on Law Enforcement Assistance Administration (LEAA), a federal anti-crime effort. Criticism made by Attorney General William Saxbe against the program; Manipulation made to data banks for political purposes; Failure of LEAA to change the substance or direction of the criminal justice system.

Since the logical structure of a data base can be represented by a tree or graph, it is quite natural for us to view the process of designing a data base as that of constructing a tree or a graph. A general method for constructing such a tree or graph is provided. There are three important elements in this general construction method; namely, a set of binary relations, an algorithm for constructing subsets of a set, and an algorithm for selecting an element from the given set of objects. The use of different relations and algorithms results in different information structures, as list, tree, ring, etc. Thus the problem of information organization and storage is reduced to that of defining relations and formulating algorithms under a given set of constraints. The results presented may be valuable to designers as useful design concepts, and may serve as a basis for developing a formal theory on the subject. [ABSTRACT FROM AUTHOR]

Data base management systems have grown rapidly in their power and complexity over the 15-year history of data processing on commercially available computers. The original concepts have split, and new terms have been adopted to name and refer to these concepts. The Data Structure Diagram graphic technique is used to illustrate the splitting of the concepts and the structural relations which exist between these concepts at each point in the evolution. [ABSTRACT FROM AUTHOR]

The article discusses the development of computer systems to monitor the fast-growing operations of airlines. According to the article, the nationwide data systems of airlines are testing the limits of the largest computers and the skills of computer professionals. It adds that about 200 million U.S. dollars are invested by the industry into electronic data processing annually. Some uses of the computers are discussed, including selling more tickets and helping boost the load-factor on aircraft.

Studies key-to-address transformation methods applied to a set of existing files. Correlation between the number of accesses required to get to a record and the number of overflows record created by a transformation; Techniques of accessing a single record of a formatted file; Guidelines for the selection of an appropriate practical transform.

Future users of large data banks must be protected from having to know how the data is organized in the machine (the internal representation). A prompting service which supplies such information is not a satisfactory solution. Activities of users at terminals and most application programs should remain unaffected when the internal representation of data is changed and even when some aspects of the external representation are changed. Changes in data representation will often be needed as a result of changes in query, update, and report traffic and natural growth in the types of stored information Existing noninferential, formatted data systems provide users with tree-structured files or slightly more general network models of the data. In Section 1, inadequacies of these models are discussed. A model based on n-ary relations, a normal form for data base relations, and the concept of a universal data sublanguage are introduced. In Section 2, certain operations on relations (other than logical inference) are discussed and applied to the problems of redundancy and consistency in the user's model. [ABSTRACT FROM AUTHOR]

Studies synchronization in a parallel-accessed data base. Simultaneous manipulation of a data base by more than one process; Rules for synchronization to maximize the amount of parallel activity; Representation of the data base as a graph; Hierarchy of directories for an on-line file system; Validity of the methods for synchronization of processes.

Provides information on data files which are an integral part of a data processing system. Importance of the selection of an organization for the data within the file to the system's operating efficiency; Techniques which may be used for organizing structured data; Provision of a reference which allows the designer to limit the number of file organizations considered for the system.

The article discusses the U.S. Census Board's April 1, 1970 head count of the entire population in the U.S. According to the article, there is controversy over the possibility of a national data bank, with opponents arguing that it will put to work for the state detailed central record files on everybody. Some benefits of the census information on businesses and general welfare are discussed, including manufacturers' learning where potential customers live and how many of them there are. INSET: Black power in the numbers.

The article discusses issues regarding the conservation of natural resources in the U.S. It says that the problem facing the country lies in the fact that no single database exists on how such resources are used. When environmental degradation occurs causing people to act, they do so in separate areas. If their complaints are addressed, it claims that the redress is only superficial. It suggests that a single federal body be set up to monitor the environment and that policies be set which are preventive in nature.

Focuses on the researcher C.V. Bachman's stimulating 1973 Turing Award Lecture. Discussion on the exploration of the potential in data base usage;Report that information processing has been an intellectual concern of philosophers through the ages; Information about the establishment of successful usage of mechanized data bases prior to the computer era.

The article discusses the testimony of the chairman of the Association for Computing Machinery (ACM) Special Interest Group on Computers and Society, Robert P. Bigelow, at the hearings on Computers, Data Banks and the Bill of Rights. He emphasized that data banks need to be regulated. He believes that there are two folds effect of computer in favor of privacy. It creates awareness among citizens and legislators regarding dangers from private and government data banks. Economical updating, correction, and deletion of individual data have also been made possible by it. With the help of a separate agency, the data bank regulation will be uniform and the technological advances will be positively effected.

The article focuses on the U.S. Standard Data Code for Calendar Date for Machine-to-Machine Data Interchange. The purpose of this standard is to provide a standard means of recording calendar date to facilitate interchange of data between the machines of data systems. Calendar date is a data group identifier composed of the data elements year of century, month of year, and day of month. Year of century shall be encoded by the two low order digits of the conventional numeric designation of the Gregorian calendar year. The Standard Data Code for Calendar Date is intended to be a member of a family of data codes for time to be developed for the full range of needs for data codes for time in the interchange of data between the machines of data systems. The high to low sequence of data elements is proposed for the following reasons: It is consistent with the sequence of data element codes already used in identifying other times; it provides a foundation for building a system of identifiers to times; it is consistent with the sequence of individual identifying terms used essentially universally in other subject areas.