Creating Databases for Web Applications

1
Creating Databases for Web Applications

• Work session
• Open Source versus Proprietary
• important topics
• HW finish projects. Look at final quiz guide.
  Final posting.

2
Final posting

• post your considered, reasoned opinion on Open
  Source vs proprietary asp versus php Access
  versus MySql or any related issue.
• Catch up on other postings.

3
Postings php vs asp, etc.

• Proprietary can be companies other than
  Microsoft. For example, Cold Fusion is product of
  Macromedia (formerly Allaire).
• Keep in mind that there are many topics,
  functions, relevant standards,etc. in these
  systems that we did not cover.

4
Things to consider

• things to store away in the back of your mind
  for consideration when building a 'real' Web
  application.

5
Performance

• Performance of Web sites governed by connection
  AND site itself.
• presence of large images, other large files, big
  consideration.
• Some DBMS provide for stored procedures that
  carry out a query. Sometimes these can involve
  parameters. This is a way to improve
  performance. The function is compiled and not
  interpreted.
• Some DBMS provide for (extra) index fields
  besides the primary key. This is another way to
  improve performance.

6
Important topics

• multiple (concurrent) users of database
• DBMS may handle this.
• single table versus multiple tables
• transaction concept
• writing/updating across multiple tables
• paging
• handling of larger recordsets

7
Important topics, continued

• scaling up application
• multiple users many, many users
• larger tables
• maintenance of program
• version control
• backup
• databases
• scripts / code
• data base administrator
• data dictionary
• 'quality assurance'
• test suite
• bug/feature list
• investigate how bugs happen

8
Important topics, continued

• disaster control
• backup data stores
• backup procedure
• security
• hackers
• insiders
• Note security protections also help in benign
  situations knowing where you need to look and
  where you don't need to look to uncover problems.

9
Reminder Objects

• are information procedures
• properties methods
• attributes operators
• information behavior
• can be defined by you, the programmer.
• DOM is the Document Object Model used for client
  side (for example, document.write( ) ).
• asp is essentially a set of objects (Request,
  Response, etc.) called the intrinsic objects.
• php support resembles other oo languages more
  than JavaScript (maybe more than VBScript?)

10
php example (partial)

• class node
• var mparent var mfirstchild var mnextsib
  var mname var mlocation
• function Node (parent, name, location)
• this-gtmparent parent
• this-gtmnamename
• this-gtmlocationlocation
• function addchild(child)
• if isset(firstchildthis-gtmfirstchild)
• firstchild.addsib(child)
• else this-gtmfirstchildchild
• function addsib(sib)

constructor method
ends class
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php example
see next

• newnode new Node (current, 'curley', 'NYC')
• invokes a call to the constructor function node,
  which sets up an instance of a node.
• current.addchild (newnode)
• this invokes the method of current that will
  connect it to newnode.
• Access object properties
• current.mlocation

12
more php

• inheritance
• class specialcustomer extends customer
• overriding
• re-use name of method
• reference operator (pointer)
• place node place will refer to same
  thing, not a copy
• eval (string) evaluates the contents of
  string.

13
JavaScript OO support

• Limited, but can use functions in a var statement
  and can name a procedure as a property.
• connects data and code
• Neither php nor JavaScript has information hiding
  mechanisms
• This is not for keeping something secret as much
  as for catching an error during compilation that
  would otherwise lead to a logical, runtime error.
• no inheritance support
• building objects from other objects to save
  redundant coding AND have the system apply the
  appropriate procedure.

14
JavaScript OO support basic

• var node new Object()
• node.mname "curley"
• node.addchildaddchild

a function defined elsewhere
15
JavaScript example using constructor

• function node (parent, name, location)
• this.mparent parent
• this.mname name
• this.mlocation location
• this.addchildaddchild
• this.addsib addsib
• function addchild (child)
• function addsib (sib)

this is term for thing being created.
16
JavaScript example usage

• var person new node (parent, 'moe','nyc')
• parent.addchild(person)
• person.mlocation

17
Benefits of oo

• Encapsulates information and treatment of
  information to make code either to maintain and
  to re-use
• only one place to check and to modify if you need
  to change how you 'add a child' in the previous
  example.
• catches errors as compilation (syntactic) errors.

18
Emerging technologies, infrastructure

• broadband
• wirelesssmaller devices
• WAP, XML, XSL, XSLT, WML
• Application Service Providers
• new/not so new offerings
• Cold Fusion
• asp.net, vb.net, Active X objects (for sale)
• Open Source
• php 4.3.6 www.php.net

19
XML

• Building XML applications with Java
• Larger applications requiring communication
  between components
• Creating User Interfaces
• xml and xslt, also wml, VoiceXML

20
Questions for final quiz

• See guide to final quiz posted online.
• Note final will be open book, open notes. You do
  need to study.

21
Projects

• Prepare to demonstrate and to show your
  storyboard diagram (and maybe the others diagrams
  as reminders).
• Prepare hardcopy of diagrams plus choice essay if
  you needed to do one.
• Send URL of project to me!