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Connecting Databases to the Web Web Programming Technologies

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Connecting Databases to the Web Web Programming Technologies Outline Common Gateway Interface (CGI) Java Applets Server Extensions PHP Active Server Pages/ Java ... – PowerPoint PPT presentation

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Title: Connecting Databases to the Web Web Programming Technologies


1
Connecting Databases to the WebWeb Programming
Technologies
2
Outline
  • Common Gateway Interface (CGI)
  • Java Applets
  • Server Extensions
  • PHP
  • Active Server Pages/ Java Server Pages
  • What else is out there?
  • Architectures
  • Extended PHP example

3
First Generation Architecture
4
Second Generation Architecture
5
Next Generation Architecture
6
Common Gateway Interface (CGI)
  • Some files on server are interpreted as
    programsdepending on either ext., flag or
    special directory
  • Program is invoked and generates MIME header and
    HTML on stdout

Web-Server
Web-Server
File-System
HTTP-Request
Load File
HTML
HTML?
HTML-File
File
7
CGI Discussion
  • Advantages
  • Standardized works for every web-server, browser
  • Flexible Any language (C, Perl, Java, ) can
    be used
  • Disadvantages
  • Statelessness query-by-query approach
  • Inefficient new process forked for every request
  • Security CGI programmer is responsible for
    security
  • Updates To update layout, one has to be a
    programmer

8
Java Applets
Web-Server
Web-Server
HTTP-Request
Load File
File-System
HTML-File
File
Load Applet...
9
Java Applets Discussion
  • Advantages
  • Platform independent works for every web-server
    and browser supporting Java
  • Disadvantages
  • Standalone Character
  • Entire session runs inside applet
  • HTML forms are not used
  • Inefficient loading can take a long time ...
  • Resource intensive Client needs to be state of
    the art
  • Restrictive can only connect to server where
    applet was loaded from (Java VM but can be
    configured)
  • Note Server-Process can be written in any
    language

10
DB Access in Java
Java Applet
TCP/UDP IP
Java-Server-Process
JDBC Driver manager
JDBC-Driver
JDBC-Driver
JDBC-Driver
Sybase
Oracle
...
11
Server Extensions
  • Previous Approaches
  • Platform independent and standardized
  • Simple interface
  • Lots of programming necessary
  • Inefficient
  • Server Extensions
  • Server is extended with handler/module
  • One handler for all incoming requests
  • Much more efficient

12
Server Extensions The Basic Idea
Web-Server
Web-Server
HTTP-Request
File-System
Load File
HTML
HTML?
File
HTML-File
13
Server Extensions
  • API depends on Server vendor
  • Apache Foundation Apache Server Apache API
  • Microsoft Internet Information Server ISAPI
  • Netscape Enterprise Server NSAPI
  • One can define its own server extension, e.g.
  • Authentication module
  • Counter module

14
Active Server Pages
  • Active Server Pages (ASPs)
  • Available in Personal Web Server
  • Based on VBScript, Jscript
  • Modular Object Model
  • Active Server Components
  • Active Data Objects (ADO) for Databaseaccess
  • In MS .NET ASP, ADO

15
ColdFusion
Web-Server
Web-Server
File-System
HTTP-Request
Load File
HTML
HTML?
HTML-File
File
HTML
CF Script?
Cold Fusion Server Extension
16
ColdFusion Simple Query
  • Proprietary Scripting Language CFML - similar to
    other scripting languages

ltCFQUERY NAMEPersonList DATASOURCEPersonDB
gt SELECT FROM Persons lt/CFQUERYgt ltHTMLgt ltBODYgt
ltH1gt Person List lt/H1gt ltCFOUTPUT
QUERYPersonListgt ltBgtNamelt/Bgt
Name ltBgtAgelt/Bgt Age ltBgtSalarylt/Bgt Sal
ltBRgt lt/CFOUTPUTgt lt/BODYgt lt/HTMLgt
ltHTMLgt ltBODYgt ltH1gt Person List lt/H1gt ltBgtNamelt/Bgt
Tom ltBgtAgelt/Bgt 45 ltBgtSalarylt/Bgt 45000
ltBRgt ltBgtNamelt/Bgt Jim ltBgtAgelt/Bgt
38 ltBgtSalarylt/Bgt 40000 ltBRgt ltBgtNamelt/Bgt Karen
ltBgtAgelt/Bgt 26 ltBgtSalarylt/Bgt 32000
ltBRgt lt/BODYgt lt/HTMLgt
17
ColdFusion Form Handling
ltHTMLgt ltBODYgt ltH1gt Tom lt/H1gt ltULgt
ltLIgtltBgtAgelt/Bgt 45 ltLIgtltBgtSalarylt/Bgt 45000
ltLIgtltA HREFwww.tom.com
ltBgtHomepagelt/Bgtlt/Agt lt/ULgt lt/BODYgt lt/HTMLgt
ltCFQUERY NAMEPersonInfo DATASOURCEPersonDB
gt SELECT FROM Persons WHERE
NameForm.PName lt/CFQUERYgt ltHTMLgt ltBODYgt ltCFOUTP
UT QUERYPersonInfogt ltH1gt Name lt/H1gt ltULgt
ltLIgtltBgtAgelt/Bgt Age ltLIgtltBgtSalarylt/Bgt
Sal ltLIgtltA hrefURLgtltBgtHomepagelt/Bgt
lt/Agt lt/ULgt lt/CFOUTPUTgt lt/BODYgt lt/HTMLgt
ltHTMLgt ltBODYgt ltFORM ACTION"http//www.abc.co
m/cf/pf.cfm"gt ltH1gt Find Person lt/H1gt Person Name
ltINPUT NAME"PNAME"gt ltpgt ltINPUT TYPE"submit"
VALUE"Find"gt lt/FORMgt lt/BODYgt lt/HTMLgt
18
ColdFusion Misc. Issues
  • Site admin sets up data sources very similar to
    the handling of ODBC data sources in MS Windows
  • In fact ColdFusion combines techniques to access
    databases
  • Generation of HTML code
  • Java Applets embedded via ltCFGRIDgtlt/CFGRIDgt
    access the database through the application
    server
  • Application server is also gateway to database
    for the ColdFusion IDE (ColdFusion Studio)

19
PHP
  • How does PHP differ from ASP and CF?
  • Free, open source
  • Many client libraries integrated
  • Runs on any web server supporting CGIs (MS
    Windows or Unix)
  • Module version for Apache

Web-Server
Web-Server
File-System
HTTP-Request
Load File
HTML
HTML-File
PHP-File
PHP-Script
Output
PHP Module
Database APIs, other APIs SNMP, IMAP, POP3,
LDAP, ...
20
PHP A Simple Example
ltHTMLgt ltBODYgt lt?PHP db mysql_connect("loca
lhost", "dbuser") mysql_select_db("mydb",db)
result mysql_query("SELECT FROM
employees",db) ?gt ltTABLE BORDER1gt
ltTRgtltTDgtNAMElt/TDgtltTDgtPOSITIONlt/TRgt lt?PHP while
(myrow mysql_fetch_row(result))
printf("lttrgtlttdgts slt/tdgtlttdgtslt/tdgtlt/trgt\n",
myrow1, myrow2, myrow3)
?gt lt/TABLEgt lt/BODYgt lt/HTMLgt
21
PHP Misc Issues
  • Syntax Perl/C like
  • Form fields are available as variables in
    following page
  • has e.g. image and PDF generation on the fly
  • some OO features (e.g. classes)
  • The number of functions is steadily increasing

22
Java Server Pages
23
JSP ExampleHello.jsp
  • lthtmlgt
  • ltheadgt
  • lttitlegtMy first JSP page
  • lt/titlegt
  • lt/headgt
  • ltbodygt
  • lt_at_ page languagejava gt
  • lt System.out.println(Hello World) gt
  • lt/bodygt
  • lt/htmlgt

24
And the Output IS
  • lthtmlgt
  • ltheadgt
  • lttitlegtMy first JSP page
  • lt/titlegt
  • lt/headgt
  • ltbodygt
  • Hello World
  • lt/bodygt
  • lt/htmlgt

25
What Else Is Out There?
  • Java Server Pages (JSP)
  • similar to PHP
  • Java Servlets
  • very similar to CGIs
  • A couple of solutions from Oracle
  • PENN ExpressApp is based on OWS
  • various web shop applications
  • all of them use a more or less sophisticated
    scripting language
  • and a lot more ...

26
Databases Usually Used
  • ASP
  • MS Jet Engine (DB engine behind MS Access)
  • MS SQL Server
  • Oracle (ODBC)
  • ColdFusion
  • Oracle (native driver support)
  • Informix (native driver support)
  • Sybase (native driver support)
  • PHP
  • MySQL (linked in client library)
  • mSQL (linked in client library)
  • Postgres (linked in client library)
  • Oracle (linked in client library)

27
Architectures
  • The architecture type depends on kind and number
    of servers involved
  • Different archictures different advantages and
    disadvantages
  • Generally we can distinguish between different
    types
  • 2-tier architecture
  • 3-tier architecture
  • n-tier architecture
  • What matters SPEED

28
2-tier Architecture
  • Web server plus module connecting to database,
    LDAP, IMAP, ...

1
Web-Server
Module
2
DB
Directory
Mail Server
SNMP
29
2-tier Architecture
  • Advantages
  • easy and fast to setup
  • easy to administrate
  • Disadvantages
  • not fail safe (single point of failure)
  • scales badly on high loads

30
3-tier Architecture
  • Web server plus application server connecting to
    database, IMAP, ...

1
Web Server Cluster
2
Application Server Cluster
3
Other Servers Cluster
DBRepl.
DB
DB
Mail Server
SNMP
31
3-tier Architecture
  • Advantages
  • better scalabilty
  • more reliable through failover mechanisms
  • offers better load balancing
  • Disadvantages
  • complicated to set up an maintain

32
Architectures Usage
  • 2-tier
  • Apache-PHP plus Database etc.
  • 3-tier
  • ColdFusion 4.x, BEA Weblogic
  • Oracle Web Application Server?
  • n-tier
  • big sites with custom systemslike Yahoo,
    Amazon.com, eBay
  • Classification not always 100

33
Technology Choices
  • PHP/OraclemySQL
  • ASP/Access/ODBC -- Need MS IIS
  • JSP/OraclemySQL/JDBC -- Need Tomcat or
    ApacheJServ
  • Any Other Choices?

34
Extended PHP Example
35
Extended PHP Example
36
Plain HTML
ltHTMLgt ltTITLEgtSimple SQL Web Interface for Movie
Tablelt/TITLEgt ltBODYgt ltH1gtSimple SQL Web Interface
for Movie Tablelt/H1gt PHP code here ltFORM
ACTION"query.php3" METHODGET
ENCTYPE"TEXT/PLAIN"gt ltINPUT SIZE100
MAXLENGTH250 NAME"query" VALUE"select
title, year, mid from movies"gt lt/FORMgt lt/BODYgt lt
/HTMLgt
37
Table Generation (Part 1)
lt?php / check for query, if empty describe
movies / if (!isset(query)) query
"describe movies" else query
stripslashes(query) print "ltBgtYour query
lt/Bgt\"" . query . "\"\n" result
mysql_query(query, conID) or die ("Invalid
query") // disable error reporting eLevel
error_reporting(0) ?gt
38
Table Generation (Part 2)
lt?php / generate table header or catch INSERT,
DELETE and UPDATE statements / if
(mysql_affected_rows(conID) gt 0) print
"ltBgtaffected " . mysql_affected_rows(conID) . "
row(s)!lt/BgtltPgt\n" if (mysql_num_rows(result) gt
0) noFields mysql_num_fields(result) pr
int "lttable border\"1\"gt\nlttrgt\n" for (i
0 i lt noFields i) print "ltthgtltbgt" .
mysql_field_name(result, i) .
"lt/bgtlt/thgt\n" print "lt/trgt\n" while (row
mysql_fetch_array (result)) print
"lttrgt\n" for (i 0 i lt noFields i)
print "lttdgtnbsp" . rowi .
"nbsplt/tdgt\n" print "lt/trgt\n"
print "lt/tablegt\n" ?gt
39
Links
  • Software
  • Apache http//www.apache.org/
  • ASP http//msdn.microsoft.com/workshop/server/de
    fault.asp
  • ColdFusion http//www.allaire.com/coldfusion/
  • MySQL http//www.mysql.com/
  • Oracle http//www.oracle.com/
  • Oracle Technet http//technet.oracle.com/
  • PHP http//www.php.net/, http//www.zend.com/
  • Others
  • cnet http//www.builder.com/
  • DevShed http//www.devshed.com/Server_Side/
  • Webmonkey http//www.webmonkey.com/
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