Before we begin…

© 2006 ITT Educational Services Inc. Course Name: IT390 Business Database Administration Unit 1 Slide 1

Before we begin…

• Introduce yourself. Do mention something about your educational and professional backgrounds.

• What are your goals for graduation?

What do you want to do??


Unit 1:

Database History, Models, and Structure

IT 390 - Business Database Administration


Primary Lesson Objectives

• Explain the history, basic models and components of databases.

• Identify the importance of Relational Algebra, SQL, and ERD Diagrams.


More Details…

• Identify the components of a database and their uses. • Define DBMS and RDBMS. • Identify the differences between DBMS and RDBMS. • Identify the features and functionality of RDBMS.• Identify the data models used for organizing data.• Identify the types of databases and their functionality.• Analyze the E-R data model.• Identify the object-oriented logical data model.• Explain the basic components of databases.


Databases: An Overview

• Databases are organized collection of related data.• Databases can contain data of the following data

types at a single location: Text Graphic Audio Video

• An example is a Hotel which has a “guest” list with details about guest (room number, length of stay, mini-bar tab, etc.)


Features of a Database

• A database has the following features: Stores data in an organized manner. Searches and retrieves the stored data. Maintains a single copy of the data. Provides security to the stored data.

• Several corporations produce database software products. Two BIG players are Microsoft and Oracle


Database?………I thought I was a __________ Guru???


Data and Information• Data are raw facts that may or

may not be useful for the user.• Information is processed data

that holds some meaning to the user.• A physical database is just a file cabinet.


Data Sharing instead of physical duplication• Data sharing is defined as a process by which the

data stored at a single location can be simultaneously accessed and modified by multiple users.

• Data sharing aims at reducing the duplicity of data.


Class Activity

• Which of the following has the most similar structure to that of a database? A library of books A store containing paper and pens A car A video cassette


Solution

• A library resembles the structure of a database. This is because as books are arranged in each bookshelf of a library, similarly, data is stored and arranged in a database.


Class Activity- Data vs. Information

• From the list below classify which of the following is data and which is information: 12 12*8=96 There are two people in the room. Room


Solution

• Data is: 12 Room

• Information is: 12*8= 96 There are two people in the room


Class Activity- data sharing vs. non-sharing

• In a track and field sports meet, multiple events are being conducted at different venues. The overall results need to be declared and compared, but the results for the track and field events have not been updated properly or in a timely manner.

• The result is angry participants and confused spectators. What is this called in database terms?


Solution

• Data inconsistency


Database Management Software DatabaseDBMS


Database Software Vendors


Database Advantages

• Data Integrity• Data Accuracy• Control of Data dependence• Control of Data redundancy• Better Security


Introducing Data Models

Data Model(Prototype) Database

Define the structure that needs to be conceptualized to implement a database.

Data models are:

A set of data structure types

A collection of operators

A set of integrity rules

You can view data model as a prototype of a database. It’s the framework for the way we want to implement our database.


The Relational Database Model



Tables, also called RELATIONS

• Tables are a collection of records that are arranged in the following format: Rows (Records or Tuples) / Horizontal Columns (Fields or Attributes) / Vertical

StudID StudName StudAge

S001 Jack 21

S002 Mary 20

S003 Kate 22

S004 Patrick 19

Columns

Row

s


Components of a Database

• The main components of a database are: Record

Table

S003 Kate 22

StudID StudName StudAge

S001 Jack 21

S002 Mary 20

S003 Kate 22

S004 Patrick 19


Relational Database Management System• An RDBMS has the following components:

Relation (table) Tuple (record or row) Attribute (column or field)


Other Types of Data Models

• Record-based logical models• Network Model (Interconnected)• Hierarchical Model

(Tree structure)

• Object-based logical models


File or Record-based Model

The data is structured in fixed format records.

For example, a firm that has outsourced its processes to (partners in) multiple locations might NEED to use a record-based logical model.

The partners might not have the same database system.


Network Data Model


Hierarchical Data Model


Linux as an example of the Hierarchical Model



Object-Based Logical Models

Attributes

Color

Model

Entity Car

For example, an automobile design firm that stores its information for designing car models might use an object-based logical model.


More About Object-oriented Data Model (OODM)

The Object-oriented data model (OODM) covers: Implementation for complex or large objects called

BLOBs (Binary Large OBjects) like images. High compatibility with Object-oriented programming

languages, such as C++ and Java.


Class Activity

• Identify the type of database that needs to be used for the scenario: A company needs to store information

including pictures on different types of automobiles, parts and their common characteristics, such as model, wheels, and weights.


Solution

• An Object-oriented database is suited for the scenario.


Class Activity

• Identify the type of database that needs to be used for the scenario. A company needs to store text information

on various departments of an organization.


Solution

• A Relational database is suited for the scenario.


Class Activity

• Identify the type of database that needs to be used for the scenario. A garment manufacturing unit wants to store

information of their product text feedback, such as shrinkage, color, and texture. In addition, the unit wants to integrate modeling video of various garments into the existing organizational database.


Solution

• An Object-relational database is suited for the scenario.


Class Activity

• Identify the components of OODM: Car Vehicle Ignition Motor-Bike Two-wheeler Shifting gears Four-wheeler


Solution

• The Objects are: Car Motor-Bike

• The Methods are: Ignition Shifting-gears


Solution (cont.)

• Identifying Inheritance

(letting other objects inherit characteristics)

Vehicle

Two-wheeler Four-wheeler


Three-tiered Visualization











Database Domains




Class Activity- Keys

• What should be the primary key in the following table structure of Employee_LoansTaken table: Employee name Amount of loan taken Type of security Employee ID code Amount still payable


Solutions

• Employee code should be the primary key because: Employee ID code is unique for each

employee. Employee ID code cannot be blank (NULL). Other fields, such as employee name can

have same values for multiple occurrences.


Class Activity • Identify the Entities and Attributes in the

figure:• What do the symbols mean in ERD

diagrams?


Solutions• The Entities are:

Square Circle Triangle

• The Attributes are: Size Color

• The Symbols mean: Rectangle or Square is an Entity/table Oval or Circle is an attribute Diamond or Triangle is a relationship


Entity-Relationship Model

• An approach to representing data in a database

• Entities are drawn as rectangles

• Relationships are drawn as diamonds with lines connecting the entities involved in relationships


One-to-many relationship


Many-to-Many Relationship


Many-to-Many Relationship


One-to-Many Relationship


Many-to-Many Relationship with Attributes


Composite Entity

• Composite entity - an entity that exists to implement a many-to-many relationship

Essentially both an entity and a relationship

Represented in an E-R diagram by a diamond within a rectangle


Composite Entity


Complete E-R Diagram


E-R Diagram with an Existence Dependency and Weak Entity

• Existence dependency - when the existence of one entity depends on the existence of another related entity

• Indicate an existence dependency by placing an “E” in the relationship diamond

• Weak entity - an entity that depends on another entity for its own existence

• A double rectangle encloses a weak entity


E-R Diagram with an Existence Dependency and Weak Entity


Cardinality

• Cardinality - the number of items that must be included in a relationship

• An entity in a relationship with minimum cardinality of zero plays an optional role in the relationship

• An entity with a minimum cardinality of one plays a mandatory role in the relationship


E-R Diagram that Represents Cardinality


• Integrates the existing data into a common uniform framework.

• Provides security and efficient fault-and-performance management for DBAs.

• Is of two types:

Native database middleware

Database generic middleware

Database Middleware






Summary• Database design is a two-part process of

determining an appropriate database structure to satisfy a given set of requirements

• A user view is the set of necessary requirements to support a particular user’s operations

• A database design is represented in a language called Database Design Language (DBDL)

• Designs can be represented pictorially using entity-relationship (E-R) diagrams


Summary• Advantages to both top-down and bottom-up

approaches• One-to-One and One-to-Many relationships require

attention to primary keys• Entity-relationship (E-R) model is a method of

representing the structure of a database using an E-R diagram

• Nowadays, there are really only 2 kinds of databases, Relational and Object-oriented. Other deprecated models existed in the past like Network and Hierarchical.


• Question(s)??

• LAB TIME!!!

Before we begin…

Documents

stored data

stores data

duplicity of data

processed data

following data types

set of data structur

er data model

database history