Detailed Diagram, Data Dictionary - Database Management - Lecture Slides, Slides of Introduction to Database Management Systems

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Database

Management

Systems

Lecture - 6

In Previous Lecture

We were discussing Context Diagram that…..

Detailed Diagrams

Show processes in successive levels of detail

shows major sub-processes

Detailed Diagrams

Outline numbering  1.1, 1.2, …, 1.n Level one, shows internal details for each major sub- process  1.1.1, 1.1.2,…1.1.n Level two

Detailed Diagrams

All process have both inputs and outputs  Outputs must differ from inputs Child diagrams and parent process must have same input/output

Detailed Diagram

Data Dictionary

May be integrated or freestanding

Integrated is referred by DBMS

Freestanding as a CASE tool

Cross Reference Matrix

A Data Dictionary tool Used to link different things, like functions to entities, or requirements to attributes Can be manual even

Summary

Analyze User Environment or

Preliminary Study + Requirements Analysis

Use of CASE or manual tools

Database Design

Phase

Database Modeling

Process of creating a logical representation of the structure of the database

The most important task in database development

Points to Remember

A database must mirror the real world. Only then can it answer questions about the real world! The emphasis of data modeling is on representing reality

Data Model

Created using a data model

Data Model: is a set of tools or constructs that is used to construct a database design

Components of a DM

Structures Manipulation language Integrity constraints Beep beep, caution