Topic 2 - Topic 2: Data, Databases, and DBMSs Before you...

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Topic 2: Data, Databases, and DBMSs Before you can understand complex data organization systems, the building blocks of those systems must be understood. This topic investigates the evolution of data storage and retrieval techniques and the emergence of database management systems. We also introduce basic terminology used in the organization of data. The differences between traditional flat file systems and database management systems are discussed. The conceptual models for database management systems (DBMS) are briefly introduced and the major components included in DBMS are defined. After reading this topic, you should be able to: Discuss the evolution of the techniques for data storage and retrieval. Describe various models for the organization of data. Discuss sequential vs. random file access methods. Describe the advantages of database management systems over flat file systems. Describe the historical significance of the hierarchical, network, and relational database conceptual models as well as the emergence of object-oriented databases. List the features of database Management Systems (DBMS). Lesson 1: Flat File Data Organization and Access Methods Organizations in the past never had the opportunity to exploit database and database management systems. In the past, much of this information was kept in paper form, or on a mainframe computer. Many of these were flat file systems, which made it much harder to store, access, retrieve, and manipulate data. This lesson will explore the evolution of database systems. After reading this lesson, you should be able to: Describe the evolution of flat file storage techniques and database models Show a time line illustrating the evolution of flat file systems and various types of database models Describe the data hierarchy Describe types of data storage and retrieval used in flat file systems Define sequential file access and random file access Describe how an index is used to achieve random file access Create an index on a data file The Data Hierarchy and Flat File Data Storage In order to understand the way in which data are stored on computer systems, the student should first understand the data hierarchy, that is, the way that data are grouped from the smallest bit to the largest database. Data Hierarchy
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This is very important, throughout the rest of this course these terms and this hierarchy will be referenced in other definitions and explanations. A bit is the smallest piece of information that can be stored either in primary memory of the CPU or on one of the peripheral storage devices (like disk, tape, or CD). A bit represents a 0 or a 1. All other information that is stored is some combination of zeros or ones. A byte contains a sequence of 8 bits. One text character is stored in one byte based on either the standard Extended Binary Coded Decimal Interchange Code (EBCDIC) or American National Standard Code for Information Interchange (ASCII) codes. These codes are internationally standardized. When a user
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This note was uploaded on 08/02/2009 for the course IST 210 taught by Professor Mcconn,charlotteryoo,jungwoo during the Summer '08 term at Pennsylvania State University, University Park.

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Topic 2 - Topic 2: Data, Databases, and DBMSs Before you...

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