Download Databases - Pub HTML5

Databases
Nanda Ganesan, Ph.D.
Objective
Q1: What is the purpose of a database?
Q2: What is a database?
Q3: What is a database management
system (DBMS)?
Q4: How do database applications make
databases more useful?
Q5: What is a NoSQL DBMS?
Copyright © 2015 Pearson Education, Inc.
Q3: What Is a Database
Management System (DBMS)?
• Program used to create, process, and
administer a database
• Licensed from vendors such as IBM,
Microsoft, Oracle, and others
• DB2 from IBM, Access and SQL
Server from Microsoft, Oracle
Database from Oracle Corporation
• MySQL - open source, license-free for
most applications Copyright © 2015 Pearson Education, Inc.
Database Definition
• Database Management System (DBMS)
– Access, Oracle etc.
• Database Application Systems
– Student enrollment management system,
enrollment management system
Data and Information
• Data
– Unprocessed
• Information
– Processed
Q1: What Is the Purpose of a
Database?
• Organize and keep track of things
• Keep track of multiple themes
• General rule:
 Single theme - store in a spreadsheet
 Multiple themes - use a database
Copyright © 2015 Pearson Education, Inc.
A List of Student Grades Presented
in a Spreadsheet – Single Theme
Copyright © 2015 Pearson Education, Inc.
Student Data Shown in a
Form, from a Database
Copyright © 2015 Pearson Education, Inc.
Data Processing
• Data Integrity
– Database is as valid as the correctness of
the information stored and processed
– GIGO
Good Information
Characteristics
•
•
•
•
•
•
•
Accurate
Verifiable
Timely
Organized
Accessible
Useful
Cost-effective
Data Hierarchy
Field1
(Primary)
Record 1
File 1.1
Database
Application 1
Record 2
File 1.2
Database
Server
Database
Application 2
Field 2
File 2.1
Q2: What Is a Database?
Copyright © 2015 Pearson Education, Inc.
Hierarchy of Data Elements
Copyright © 2015 Pearson Education, Inc.
Components of a Database
Copyright © 2015 Pearson Education, Inc.
Example of Relationships Among Rows
Copyright © 2015 Pearson Education, Inc.
Sample Metadata (in Access)
Database Components
File Characteristics
Data Types
Text
Numeric
Date
Memo
Object
AutoNumb
er
Yes/No
Attachment
Currency
Hyperlink
Data Dictionary
Maintaining Data
•
•
•
•
Add
Modify
Delete
Validate
Data Validation
Alphabetic/Nume
ric Check
Range check
Completeness
check
Check digit
Consistency check
Evolution of Database
Management Systems
•
•
•
•
File processing system
Hierarchical database systems
Relational database systems
Object oriented database systems
File Processing and Database
System
Advantages of Database
Systems
•
•
•
•
Reduced data redundancy
Improved data integrity
Efficiently shared data
Relatively simple development
Examples of Database
Management Systems
Q4: How Do Database Applications Make
Databases More Useful?
• Database application
– Collection of forms, reports, queries and
application programs serves as
intermediary between users and database
data.
• Application programs
– Provide security, maintain data
Copyright
© 2015 Pearsonand
Education,
Inc.
consistency,
handle
special cases.
Specific Purposes of Four Elements
of a Database Application
Copyright © 2015 Pearson Education, Inc.
Traditional Forms, Queries,
Reports, and Applications
Copyright © 2015 Pearson Education, Inc.
Browser Forms, Reports,
Queries, and Applications
Copyright © 2015 Pearson Education, Inc.
Browser Report for
SharePoint Site
Copyright © 2015 Pearson Education, Inc.
Access Database
Components
•
•
•
•
•
•
•
Tables
Queries
Forms
Reports
Macros
Modules
Visual Programming (Visual Basic)
Relational Database
• The entity-relationship model
• Entities (objects)
– Students, classes etc.
• Relationships
– Enrollment (Student to Classes)
Types of Relationships
•
•
•
•
One-to-one
One-to-Many
Many-to-Many
A design example
– Creating tables to capture a database
Querying the Tables and the
Database
• Query by Example
• Query Language
– SQL is the most popular query language
Processing the Database
• Structured Query Language - SQL (see-quell)
– International standard
– Used by most popular DBMS
INSERT INTO Student
([Student Number], [Student Name], HW1, HW2, MidTerm)
VALUES (1000, ‘Franklin, Benjamin’, 90, 95, 100);
Copyright © 2015 Pearson Education, Inc.
Sample SQL Statement
Administering the Database
• Used to set up a security system involving
user accounts, passwords, permissions,
and limits for processing.
• Permissions can be limited in very specific
ways.
• Backing up database data, adding
structures to improve performance of
database applications, removing unwanted
data.
Copyright © 2015 Pearson Education, Inc.
Other Database Models
• Object oriented database model
– Contains code and data
• Multidimensional database
– In comparison, relational database is a
two-dimensional database
• Web database
– Back end database to a front-end web
server
Database Personnel
• Database analyst
• Database administrators
• Database users
Experiencing MIS InClass Exercise 5:
How Much Is a Database Worth?
• Data has resale value.
• Data on everything customers do.
• Use to target customer for offerings they
care about, avoid those they don’t.
• Costly and difficult to replace data
collected over many years.
Copyright © 2015 Pearson Education, Inc.
Other Database Terms
• Data warehouse
• Data mining
Big Data
• The processing of large amount of data
– FaceBook
– Supermarkets
Q5: What Is a NoSQL DBMS?
NOSQL DBMS (NotRelational DBMS
• Supports very high transaction rates
• Relatively simple data structures
• Replicated on many servers in the cloud
• Examples
• Dynamo (Amazon)
• Bigtable (Google)
• Cassandra (Facebook)
Copyright © 2015 Pearson Education, Inc.
Will NoSQL Replace
Relational DBMS Products?
•Conversion very expensive and
disruptive.
•Very technical, limited to those with a
deep background in computer science.
•Requires years of training to use.
•Organization may choose NoSQL
products for specialized applications.
Copyright © 2015 Pearson Education, Inc.
Guide: No, Thanks, I’ll Use a Spreadsheet
• Story of the failed database project
• Database works but doesn’t meet the requirements of
this salesperson.
• Cause of database failures usually either
incompetent database developers or
underfunding.
• Causes of systems development failure--poor
communication between users and systems
developers, lack of clear requirements, and
inability to manage requirements.
Copyright © 2015 Pearson Education, Inc.
Guide: No, Thanks, I’ll Use a Spreadsheet
(cont'd)
• Databases take time to build.
• Complicated to operate.
• Need IS people to create and keep them
running.
• Salesman doesn’t want to share data.
• Spreadsheets sometimes better option,
especially if data needs are simple.
Copyright © 2015 Pearson Education, Inc.
Case Study 5: Fail Away with
Dynamo, Bigtable, and Cassandra
• Current relational DBMS products not
designed for large, multi-server systems
• NoSQL databases – Dynamo (elastic),
Bigtable (elastic), Cassandra (used by
Facebook, Twitter, Digg, Reddit)
• Amazon: Dynamo
• Google: Bigtable processes petabytes of
data on hundreds of thousands of servers
Copyright © 2015 Pearson Education, Inc.
Case Study 5: Fail Away with
Dynamo, Bigtable, and Cassandra
• Current relational DBMS products not
designed for large, multi-server systems
• NoSQL databases – Dynamo (elastic),
Bigtable (elastic), Cassandra (used by
Facebook, Twitter, Digg, Reddit)
• Amazon: Dynamo
• Google: Bigtable processes petabytes of
data on hundreds of thousands of servers
Copyright © 2015 Pearson Education, Inc.
END