CS 4400 Chapter Notes - Chapter 2: Diagram, Concurrency Control, Query Language
24 Dec 2017
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Document Summary
Client/server dbms architecture, system functionality is distributed between two types of modules. Client module: designed to run on a user workstation of prc. Server module: handles data storage, access, search and other functions. Data abstraction: suppression of details of data organization and storage; highlighting essential features for better understanding of data. Purpose is so that different users can get data at their preferred level of detail. Data model: collection of concepts that is used to describe the structure of a db provides means to achieve this abstraction. Structure of db: data types, relationships and constraints that apply to the data. Most data models have a set of basic operations for retrievals and updates on the db. Dynamic aspect or behavior of a db application specified; tells user what are operaitions that are allowed on db objects. High-level/conceptual data model: provide concepts close to way users percieve data. Entity: real-world object or concept described in db.
