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0. Chapter 5. Database Concepts. Why Study Databases?. All most all Information Systems use an underlying Database to store information Because Databases are v astly superior to spreadsheets and file processing systems. Why Study Databases?.

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Chapter 5

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Chapter 5

0

Chapter 5

Database Concepts


Why study databases

Why Study Databases?

  • All most all Information Systems use an underlying Database to store information

  • Because Databases are vastly superior to spreadsheets and file processing systems


Why study databases1

Why Study Databases?

  • Databases have NOT changed much in almost 40 years.

    • Because it is a great framework for storing data

  • Overtime, the entire world has embraced the same standard framework

    • Databases will not go away anytime soon.


Foundation data concepts

Foundation Data Concepts

Abstract Concepts

  • Entity – person, place, object or event – stored as a record or a table row

  • Attribute – characteristic of an entity – stored as field or table column


Foundation data concepts1

Foundation Data Concepts

Large

Database Concepts

  • Database – a collection of related tables

  • Tables – a collection of related records – collection of related entities

  • Record – collection of fields (table row) –represents an entity

  • Field – collection of characters (table column) – represents an attribute

  • Character – single alphabetic, numeric or other symbol

Small


Fields

Fields

  • Characters “B R E I M E R” form a field

  • A field is an attribute of an entity


Records

Records

  • A bunch of fields form a record

  • A record is an entity


Tables

Tables

  • A bunch of records forms a table

  • A table is a group of related entities


Databases

0

Databases

  • A bunch of tables form a database

  • A database can represent a single business or an entire market


Databases1

0

Databases

  • But, databases are not just a bunch of tables

  • A database also includes relationships between the different tables


Types of relationships

ThingA

ThingB

Relationship

Man

Woman

Married

Types of Relationships

One to One

  • Examples?

  • Analysis Technique

    • Consider ThingA and ThingB

    • Can ThingA be related to more than one ThingB?

    • Can ThingB be related to more than one ThingA?

    • If the two answers are NO, then it is a one to one relationship.


Types of relationships1

Student

Faculty

Student

Student

Advises

Get Advisement

Types of Relationships

One to Many

  • Examples?

  • Analysis Technique

    • Consider ThingA and ThingB

    • Can ThingA be related to more than one ThingB?

    • Can ThingB be related to more than one ThingA?

    • If only one answer is yes, then you have a one to many relationship


Types of relationships2

Student

Course

Student

Student

Course

course has a student

Student

student takes course

Types of Relationships

Many to Many

  • Examples?

  • Analysis Technique

    • Consider ThingA and ThingB

    • Can ThingA be related to more than one ThingB?

    • Can ThingB be related to more than one ThingA?

    • If the answers are yes and yes, then the relationship is many to many.


How to model relationships

How to Model Relationships


Chapter 5

Find the name and hire date of the manager working on the sales manual project


Traditional file processing sucks

Traditional File Processing Sucks

File Processing:

  • Data is organized, stored, and processed in independent files of data records

  • Sometimes the files are spreadsheets

  • Sometimes they can can even be Word or Text Documents (eeeck!)


Problems of file processing

Problems of File Processing

  • Data Redundancy –

    • duplicate data requires update to many files

  • Lack of Integration –

    • data stored in separate fileshard to combine data

  • Data Dependence –

    • changing the file format requires changing the program…


Database management approach

Database Management Approach

  • Consolidates data records into one CENTRAL database that can be accessed by many different application programs.


Database management software dbms

Database Management Software (DBMS)

Definition:

  • Software that controls the creation, maintenance, and use of databases


Dbms software components

DBMS Software Components

  • Database Definition

    • Language and graphical tools to define entities, relationships, integrity constraints, and authorization rights

  • Application Development

    • Graphical tools to develop menus, data entry forms, and reports


Dbms software components1

DBMS Software Components

  • Transaction Processing

    • Controls to prevent interference from simultaneous users and

    • Controls to recover lost data after a failure

  • Database Tuning

    • Tools to monitor and improve database performance


Database interrogation

Database Interrogation

Definition:

  • Capability of a DBMS to report information from the database in response to end users’ requests

  • Query Language – allows easy, immediate access to ad hoc data requests

  • Report Generator - allows quick, easy specification of a report format for information users have requested


Natural language vs sql queries

Natural Language vs. SQL Queries


Schemas

Schemas

Schema - A description of the database

Subschema – describes a subset of the database and which users have access to this subset


Data definition language

Data Definition Language

  • Language Used to describe Schemas and Subschemas

  • Describes relationships between different data

  • Provides a Logical view of the data


Data dictionary entry

Data Dictionary Entry

  • A more detailed description of the data in a database

  • Specifies data types and ranges

  • Assists programmers in understanding the data


Physical vs logical

Physical vs. Logical

  • DBMS concentrate on Physical access to the underlying tables

    • Concurrency control

    • Query’s

    • Creating/deleting tables


Physical vs logical1

Physical vs. Logical

  • MIS systems are (Logically) interface with a DBMS

    • monthly reports

    • charts

    • automated inquiries


Application development

Application Development

  • Today, even non-technical staff can use tools to build little programs that use a database.

    • Database Management Systems have all kinds of tools to develop custom application programs and interfaces.

  • Example: The College’s MIS (Banner) is actually an application built on top of a Oracle Database.


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