Chapter 1: The Database Environment and Development Process Essentials of Database Management Jeffrey A. Hoffer, Heikki Topi, V. Ramesh Copyright © 2014 Pearson Education, Inc.

Basic DB Terms Data: Meaningful facts, text, graphics, images, sound, video segments A collection of individual responses from a marketing research Information: Data processed to be useful in decision making Pattern of geographical buying habit based on analysis of a marketing research Metadata: Data that describes data

Data in Context Large volume of facts, difficult to interpret / make decisions

Information Useful for decision making / interpretation

Metadata Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and documentation (Data Dictionary)

Universal Database Systems DBMS Database containing centralized shared data Application #1 #2 #3

Database Systems Collection of electronic data Central repository of shared data Stored in a standardized, convenient form. Requires a Database Management System (DBMS)

Type of DB Models File processing system (traditional) Hierarchical Network Relational Object-relational

Relational Database A relational database is a collection of tables that are related to one another based on a common field. A common field is called a primary key(s). unique identifier in data model When the primary key of one table is represented in a second table to form a relationship, it is called a foreign key.

Relational Database A schematic diagram of a relational database (a) and a sample part of a relational database showing different tables (b)

Relating Tables Using a Common Field The primary key in the Employer table (EmployerID) is the common field that relates this table to the Position table. PositionID is the primary key in the Position table. The EmployerID field is a foreign key in this table. Primary keys can only have one occurrence in a table. Foreign keys may have multiple occurrences.

Relational Database Advantages Easier database design, implementation, management, and use Ad hoc query capability with SQL Powerful database management system

Database Applications Personal Database – standalone desktop database Workgroup Database – local area network (<25 users) Department Database – local area network (25-100 users) Enterprise Database – wide-area network (hundreds or thousands of users)

Collection of historic… NOT current data… Data Warehouse Collection of historic… NOT current data…

Data Mining Help to find hidden patterns and relationships in large databases to predict future behavior “If a house is purchased, then new refrigerator will be purchased within two weeks 65% of the time.”

Components of the DB Environment

Components of the DB Environment CASE Tools – computer-aided software engineering Repository (data dictionary) – centralized storehouse of metadata Database Management System (DBMS) – software for managing the database Database – storage of the data Application Programs – software using the data User Interface – text and graphical displays to users Database Administrators (DBA) – personnel responsible for maintaining the database System Developers – personnel responsible for designing databases and software End Users – people who use the applications and databases

Database Development Process Feasibility Study of Project Purpose – preliminary understanding Deliverable –request for project Requirement Analysis Conceptual Design Logical Design - Is the project worth looking at ? - Is the DB system worth building? Physical Design Implementation Maintenance

Database Development Process Purpose – state business situation and possible solution Deliverable –decomposed requirements Feasibility Study of Project Requirement Analysis Conceptual Design Logical Design What do users need and want from the new system? What the new system must do Physical Design Implementation Maintenance

Database Development Process Purpose –thorough analysis Deliverable – conceptual data model Feasibility Study of Project Requirement Analysis Conceptual Design Logical Design conceptual data model next slide example model from the web page Physical Design Implementation Maintenance

Conceptual Data Model

Database Development Process Feasibility Study of Project Purpose –information requirements structure Deliverable – logical database design Requirement Analysis Conceptual Design Hierarchical DB Network DB Relational DB Object Oriented Logical Design Physical Design Implementation Maintenance

Database Development Process Purpose –develop technology specs Deliverable – program/data structures, DB technology purchases… Feasibility Study of Project Requirement Analysis Conceptual Design Logical Design Physical Design Define physical organization of data Implementation Maintenance

Database Development Process Purpose – testing, training, debugging, installation, documenting Deliverable – operational programs, documentation, training materials Feasibility Study of Project Requirement Analysis Conceptual Design Logical Design Physical Design Implementation Maintenance

Database Development Process Feasibility Study of Project Purpose –monitor, repair, enhance Deliverable – periodic audits Requirement Analysis Conceptual Design Logical Design Physical Design Implementation Maintenance

DB Development Schedule Gantt Chart shows time estimates of tasks

DB Development Schedule … PERT Chart shows dependencies between tasks

Incremental Commitment in DB Development Project is reviewed at the end of each development phase Re-justify the process under the light of new requirements and available resources Renew commitment of stakeholders Continue / Revise Scope / Cancel