Chapter 5 Databases

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 spreadsheetMultiple themes - use a database


A List of Student Grades Presented in a Spreadsheet – Single Theme


Student Data Shown in a Form, from a Database


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

Database Server

Database Application 1

File 1.1

Record 1

Field1 (Primary)

Field 2

Record 2

File 1.2

Database Application 2 File 2.1

Q2: What Is a Database?


Hierarchy of Data Elements


Components of a Database


Example of Relationships Among Rows


Sample Metadata (in Access)

Database Components

File Characteristics

Data Types

Text Numeric AutoNumber Currency

Date Memo Hyperlink

Object Attachment

Yes/No

Data Dictionary

Maintaining Data

• Add• Modify• Delete• Validate

Data Validation

Alphabetic/Numeric Check Range check Consistency check

Completeness check Check digit

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

consistency, and handle special cases.Copyright © 2015 Pearson Education, Inc.

Specific Purposes of Four Elements of a Database Application


Traditional Forms, Queries, Reports, and Applications


Browser Forms, Reports, Queries, and Applications


Browser Report for SharePoint Site


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);


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.


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.


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)


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.


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.


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.


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


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


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Chapter 5 Databases