ADM 1370 Lecture Notes - Lecture 18: Portable Document Format, Data Redundancy, Database
11 Oct 2018
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Document Summary
Review of de nitions & concepts: database & dbms. A collection of data organized to serve many applications e ciently by centralizing data and controlling redundant and inconsistent data. Data redundancy: the presence of duplicate data in multiple data les so that the same data are stored in more than one place or location. Data inconsistency: the same attribute may have di erent values. A software package to create and maintain databases. Acts as interface between application programs and physical data les. A dbms separates the logical and the physical view of the data. Related data across tables based on common data element. Examples of relational dbms: access, oracle, dm2, ms sql server. A bookstore database with a single le named books . Relational dbms concepts: entities, entity classes, and attributes. A person, place, thing, transaction, or event about which information is stored. The rows in each table contain the entities. Customer, order, borderline, distributor, and product entity classes.
