Download Protection and a General Model

Review of Databases,
Server-side Scripting
Databases
• Database
• Database Modeling
• Relational Data Model
• Object oriented Database
• Entity Relationship Diagrams
• SQL
Database
• Database is a collection of Information.
It refers to a collection of data that is
managed by a DBMS.
A DBMS is expected to..
• Allow users to create new Databases
and specify its schema.
• Gives user ability to query and
manipulate data.
Database contd…
• Supports storage of large volume
of data, keeping it secure from
accidents and unauthorized use.
• Control access to data from many
users at once, taking care to see
that the data is not corrupted.
DBMS Architecture
Schema
Modifications
Queries
Modifications
“Query”
Processor
Transaction
Manager
Storage
Manager
Data
Metadata
Database Modeling
• The process begins with analysis of what
information the database must hold and the
relationship among components of that
information.
• The Database schema is specified in one of the
several languages or notations suitable for
expressing designs.
• After due consideration, the design is
committed to a form that can be input to the
DMBS.
Relational Data Model
• Today’s database implementations are almost
always based on Relational model.
• It has a single data-modeling concept called
the relation, a two-dimension table in which
data is arranged.
• This model supports a very high level
programming language called Structured
Query Language, SQL.
Example
Student
Student #
StudentName
Address
1
Jane Jones
First Address
2
Brian Brown
Second Address
3
Clara Clarke
Third Address
Studies
Student #
Course #
1
C1
2
T2
3
T2
Course
Course#
CourseName#
C1
Computing
T2
Technology
Example contd…
To query:
"What course does Student 2 work in?"
• go to STUDIES and look up Student 2 and return
Course# (i.e. T2)
• go to COURSE and look up T2 and return Theology
"Name all students doing Theology"
• go to COURSE and find Course# (i.e. T2)
• go to STUDIES look up T2 and return all Student#s
• go to STUDENT and find each Student# and return each
StudentName
Relational Database of a
Cat
Hammer the world flat by
normalization
Object Oriented Database
• When database capabilities are integrated with
object-oriented programming language
capabilities, the result is an object-oriented
database management system (ODBMS).
• An ODBMS makes database objects appear as
programming language objects in one or more
object-oriented programming languages.
• An ODBMS extends the language with
transparently persistent data, concurrency
control, data recovery, associative queries,
and other database capabilities.
• Object-oriented databases are designed to
work well with object-oriented programming
languages
Example
Example contd…
To query:
"What course does Student 2 work in?"
• search Students index for pointer to Student 2
• follow CoursePointer to T2 and return CourseName
(Theology)
"Name all students doing Theology"
• search Course Index and find Course# (i.e. T2)
• follow Student Pointers, looking up each Student#
This process is called navigation, note that it relies
heavily on pointers
and that a large proportion of pointers must be persistent
Oo-database of a Cat
Entity Relationship
Diagram
Student
StudentNo(PK)
StudentName
Address
Course
CourseNo(PK)
CourseName
Studies
StudentNo(FK)
CourseNo(FK)
SQL
• The Structured Query Language
(SQL) comprises one of the
fundamental building blocks of
modern database architecture.
• SQL defines the methods used to
create and manipulate relational
databases on all major platforms.
SQL contd…
SQL commands can be divided into two
main sub languages.
• The Data Definition Language (DDL)
contains the commands used to create
and destroy databases and database
objects.
• The Data Manipulation Language to
insert, retrieve and modify the data
contained within it.
Server-side Scripting
• Need
• ASP
• Coldfusion
• Perl
• PHP
NEED
• The Website creation will need
access to databases and the ability
to respond to user input.
• It also must be dynamic, scalable,
and robust.
• Old standbys XSSI and static files
just aren't sufficient to meet this
requirements.
ASP
• Active server pages can be written in
VBScript, an easy-to-learn scripting
language that uses a syntax similar to
VB.
• With the extensive integration
capabilities of Microsoft's .NET
Framework, powerful ASP pages with
expanded libraries can be created.
• IIS is required to run ASP. IIS is not
extensively stable.
• A number of applications require third
party software, which may not be free.
Coldfusion
• Simple, easy-to-learn, tag-based
Syntax.
• Its native language, CFML
(ColdFusion Markup Language)
uses fewer but more powerful
commands.
• Primitive, passable language.
• Works on variety of platforms.
PHP
• OPEN SOURCE
• Syntax borrowed from C, JAVA etc,
hence a quick learning curve.
• Dynamic graphics generation, IMAP,
SNMP, LDAP, XML .
• PHP can interface with Sybase, Oracle,
Informix, Solid, Postgres, and even
MSSQL.
• Runs on all possible web-servers.
Demonstration
A web interface for students to enroll in
courses online in PHP and Coldfusion using
MYSQL backend.
http://utopia.csis.pace.edu/cs615/demo
http://utopia.csis.pace.edu/cs615/demo/cfm