Đang chuẩn bị liên kết để tải về tài liệu:
Databases Demystified a self teaching guide phần 2

Không gian các dự án thăm dò dẫn đến nhiều sự phát triển đáng kể trong ngành công nghiệp khoa học và công nghệ, bao gồm công nghệ thông tin. Là một phần của mặt trăng Apollo của NASA dự án, Hàng không Bắc Mỹ (NAA) xây dựng một hệ thống tập tin phân cấp tên tổng quát Cập nhật phương pháp truy nhập (GUAM) vào năm 1964. | CHAPTER 1 Database Fundamentals To fully understand the OR model a more detailed knowledge of the relational and OO models is required. A Brief History of Databases Space exploration projects led to many significant developments in the science and technology industries including information technology. As part of the NASA Apollo moon project North American Aviation NAA built a hierarchical file system named Generalized Update Access Method GUAM in 1964. IBMjoinedNAA to develop GUAM into the first commercially available hierarchical model database called Information Management System IMS released in 1966. Also in the mid 1960s General Electric internally developed the first database based on the network model under the direction of prominent computer scientist Charles W. Bachman and named it Integrated Data Store IDS . In 1967 the Conference on Data Systems Languages CODASYL an industry group formed the Database Task Group DBTG and began work on a set of standards for the network model. In response to criticism of the single parent restriction in the hierarchical model IBM introduced a version of IMS that circumvented the problem by allowing records to have one physical parent and multiple logical parents. In June 1970 Dr. E. F. Ted Codd an IBM researcher later an IBM fellow published a research paper titled A Relational Model of Data for Large Shared Data Banks in Communications of the ACM the Journal of the Association for Computing Machinery Inc. The publication can be easily found on the Internet. In 1971 the CODASYL DBTG published their standards which were over three years in the making. This began five years of heated debate over which model was the best. The CODASYL DBTG advocates argued the following The relational model was too mathematical. An efficient implementation of the relational model could not be built. Application systems need to process data one record at a time. The relational model advocates argued the following Nothing as complicated as the .