Review Questions Chapter 1

1.3 Describe the approach taken to the handling of data in the early file-based systems. In the early file based system their all data was in written form, due to the lake of education, due to the in-familiarity with new techniques, lake of computer knowledge so all the data required would be stored in a file or files owned by the programs. Discuss the disadvantages of this approach.
Different programs could be written in different languages, and would not be able to access another program's files. This would be true even for those programs written in the same language, because a program needs to know the file structure before it can access it. 1.4 Describe the main characteristics of the database approach and contrast it with the file-based approach. Focus is now on the data first, and then the applications. The structure of the data is now kept separate from the programs that operate on the data. This is held in the system catalog or data dictionary. Programs can now share data, which is no longer fragmented. There is also a reduction in redundancy, and achievement of program-data independence. 1.5 Describe the five components of the DBMS environment and discuss how they relate to each other. (1) Hardware: The computer system(s) that the DBMS and the application programs run on. This can range from a single PC, to a single mainframe, to a network of computers. (2) Software: The DBMS software and the application programs, together with the operating system, including network software if the DBMS is being used over a network. (3) Data: The data acts as a bridge between the hardware and software components and the human components. As we’ve already said, the database contains both the operational data and the meta-data (the ‘data about data’).

(4) Procedures: The instructions