March 2013 Archive


Outline of Database-System Studies

Ideas related to database systems can be divided into three broad categories: 1. Design of databases. How does one develop a useful database? What kinds of information go into the database? How is the information structured? What

Database Design

“The Entity-Relationship Data Model” begins with a high-level notation for expressing database designs, called the entity-relationship model. We introduce in “The Relational Data Model” the relational model, which is the model used by the most widely adopted DBMS's,

Database Programming

The following categories cover database programming. a) Relational Algebra b) The Database Language SQL c) Constraints and Triggers d) System Aspects of SQL e) Object-Orientation in Query Languages f) Logical Query Languages We start in category “Relational Algebra” with an abstract treatment of queries in the

Database System Implementation

The subject of database system implementation can be divided roughly into three parts: 1. Storage management: how secondary storage is used effectively to hold data and allow it to be accessed quickly.

Information Integration Overview

Much of the recent development of database systems has been toward capabilities that allow different data sources, which may be databases and / or information resources that are not managed by a DBMS

Summary of The World of Database Systems

Database Management Systems: A DBMS is characterized by the capability to support efficient access to huge amounts of data, which persists over time. It is also characterized by support for powerful query languages and for durable transactions that can execute

The Entity-Relationship Data Model

The procedure to design a database starts with an analysis of what information the database must hold and what are the relationships among elements of that information. Often, the structure of the database, called the database schema, is specified in one of several

Elements of the E/R Model

The most common model for abstract representation of the structure of a database is the entity-relationship model (or E/R model). In the E/R model, the structure of data is represented graphically, as an entity-relationship diagram," using three principal element

Instances of an E/R Diagram

E/R diagrams provide details for describing the schema of databases, that is, their structure. A database described by an E/R diagram will include specific data, which we call the database instance. Particularly, for each entity set, the database instance will have a particular finite

Multiplicity of Binary E/R Relationships

Generally, a binary relationship can connect any member of one of its entity sets to any number of members of the other entity set. On the other hand, it is common for there to be a restriction on the "multiplicity" of a relationship. Assume R is a relationship connecting entity

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