chapter 1 - COP 4710: Database Systems Fall 2007...

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COP 4710: Database Systems (Introduction) Page 1 © Mark Llewellyn COP 4710: Database Systems Fall 2007 Introduction to Database Systems School of Electrical Engineering and Computer Science University of Central Florida Instructor : Dr. Mark Llewellyn markl@cs.ucf.edu HEC 236, 407-823-2790 http://www.cs.ucf.edu/courses/cop4710/fall2007
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COP 4710: Database Systems (Introduction) Page 2 © Mark Llewellyn • In the most general sense a database is simply a collection of related data. – This definition is too vague since we could consider this page of words to be a database under this definition. • Note that the “data” in a database can encompass a wide variety of objects from numbers, text, graphics, video, etc. • A more specific definition of a database consists of certain implicit characteristics which, when considered together, are assumed to define a database. What is a Database?
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COP 4710: Database Systems (Introduction) Page 3 © Mark Llewellyn • A database represents some aspect of the real world. This abstraction of the real world is often referred to as the miniworld or the universe of discourse (UoD) . • A database is a logically coherent collection of data with some inherent meaning. Random data is not typically referred to as a database, although their are exceptions. • A database is designed, built, populated, and utilized for some specific purpose. There is a set of intended users and specific applications in mind. What is a Database? (cont.)
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COP 4710: Database Systems (Introduction) Page 4 © Mark Llewellyn A database is managed by a database management system (DBMS), typically referred to as a database system . A DBMS is expected to provide significant functionality including: 1. Allowing users to create new databases. This is done via data definition languages (DDLs). 2. Allow users to query the database via data manipulation languages (DMLs). 3. Support the storage of very large amounts of data. Typically gigabytes or more for very long periods of time. Maintaining its security and integrity in the process. 4. Control access to data from many users simultaneously. What is a Database? (cont.)
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COP 4710: Database Systems (Introduction) Page 5 © Mark Llewellyn • The first commercial database systems appeared in the late 1960’s. They evolved from file systems which provide some of item (3) from the previous slide, however, they provide little or nothing from item (4). • Furthermore, file systems do not provide direct support for the features of item (2), i.e., they don’t support query languages per se. • Neither do file systems directly support item (1), their support for schemas is limited to the creation of directory structures for files. • Some of the more important early database systems were ones where the data was composed of many small items and many queries or modifications were made. Examples: airline reservation systems and banking systems.
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chapter 1 - COP 4710: Database Systems Fall 2007...

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