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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
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
0Databases
  • A bunch of tables form a database
  • A database can represent a single business or an entire market
databases1
0Databases
  • 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.
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
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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