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Data Modeling using XML Schemas

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SQL-PL Interface
Murali Mani
Some Possible Options
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Web Interface
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Perl /CGI with Oracle/mySQL
Install your own web server and use servlets with
JDBC and Oracle/mySQL
Non-Web Interface
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JDBC with Oracle/mySQL
Also other options like embedded SQL
Murali Mani
Perl Features (from Mike
Ciaraldi’s slides)
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Created around 1987 by Larry Wall.
A scripting language.
Widely used.
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Utilities
Web server programs (CGI).
Quick reference to Perl
Murali Mani
Perl – Hello World
#!/usr/local/bin/perl
use CGI::Carp qw(fatalsToBrowser
warningsToBrowser);
print "Content-type: text/html\n\n";
print ("<html><head><title>Hello World
Script</title></head>\n");
print ("<body>\n");
print ("<h1>Hello World !!!!</h1>\n");
print ("</body></html>\n");
Murali Mani
Perl – Hello World (Again !!)
#!/usr/local/bin/perl
use CGI::Carp qw(fatalsToBrowser
warningsToBrowser);
print "Content-type: text/html\n\n";
print <<ENDHTML;
<html><head><title>Hello World
Script</title></head>
<body>
<h1>Hello World !!!!</h1>
</body></html>
ENDHTML
Murali Mani
Perl – printing out environment
variables
#!/usr/local/bin/perl -w
use CGI::Carp qw(fatalsToBrowser
warningsToBrowser);
print "Content-type: text/html\n\n";
foreach $key (keys %{ENV}) {
print ("$key = $ENV{$key}<br>\n");
}
Murali Mani
Perl DBI (Data Base Interface)
module

Module that supports functions for connecting
to pretty much any DBMS software – Oracle,
mySQL, Microsoft databases through ODBC
etc.
Murali Mani
How does Perl DBI work?
(Image from OReilly)
Murali Mani
Perl DBI: Main functions
#!/usr/local/bin/perl
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
use DBI;
use configOracle;
print "Content-type: text/html\n\n";
print ("<html><head><title>Test Oracle 1</title></head>\n");
print ("<body>\n");
if ($ENV{HTTP_ACCEPT}) {
$ENV{ORACLE_HOME} =
"/usr/local/oracle/product/11.1.0/db_1";
}
$dbh = DBI->connect
("DBI:Oracle:host=$host;sid=$sid;port=$port",
$userName, $passwd) || die "Database connection not
made: $DBI::errstr";
Murali Mani
Perl DBI (contd…)
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Note the usage of DBI->connect
Also note configOracle.pm which looks like
#!/usr/local/bin/perl
package configOracle;
use Exporter;
@ISA = ('Exporter');
@EXPORT = qw($host $sid $port $userName $passwd);
$host = "oracle.wpi.edu";
$sid = "WPIDBR2";
$port = "1521";
$userName = "mmani";
$passwd = "mmani";
Murali Mani
Perl DBI (contd…)
$dropTable = $dbh->do ("DROP TABLE studentTemp");
if (!defined ($dropTable)) {
print ("error in dropping table studentTemp
$DBI::errstr<br>\n"); }
$crTable = $dbh->do ("CREATE TABLE studentTemp
(num int, name varchar (10))");
if (!defined ($crTable)) {
print ("error in creating table studentTemp
$DBI::errstr<br>\n"); }
$rows = $dbh->do ("INSERT INTO studentTemp VALUES
(1," . $dbh->quote ("Matt") . ")");
$rows = $dbh->do ("INSERT INTO studentTemp VALUES
(2," . $dbh->quote ("Greg") . ")");
Murali Mani
Perl DBI (contd…)
$st = $dbh->prepare("SELECT * from
studentTemp");
$st->execute();
print ("<table>\n");
while ($data = $st->fetchrow_hashref()) {
print "<tr><td> $data->{NUM} </td><td>
$data->{NAME} </td></tr>\n"; }
print ("</table></body></html>\n");
$st->finish();
$dbh->disconnect();
Murali Mani
Perl with mySQL

Everything stays the same except for the
connect string –
$dbh = DBI->connect
("DBI:mysql:$schema:$server", $userName,
$passwd) || die "Database connection not
made: $DBI::errstr";
Murali Mani
Perl with HTML forms and
Oracle
#!/usr/local/bin/perl
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
use DBI;
use configOracle;
use CGI ":standard";
print "Content-type: text/html\n\n";
print ("<html><head><title>Test Oracle 2</title></head>\n");
print ("<body>\n");
print ('<form method=post action=testOracle2.pl>');
if ($ENV{HTTP_ACCEPT}) {
$ENV{ORACLE_HOME} =
"/usr/local/oracle/product/11.1.0/db_1";
}
$dbh = DBI->connect
("DBI:Oracle:host=$host;sid=$sid;port=$port",
$userName,$passwd) || die "Database connection not made:
$DBI::errstr";
Murali Mani
Perl with HTML forms (contd..)
if (defined (param ("submit"))) {
$rows = $dbh->do ("INSERT INTO
VALUES (" .
$dbh->quote (param ("a1"))
$dbh->quote (param ("a2"))
if (! defined ($rows)) { print
$DBI::errstr<br>\n"); }
}
$st = $dbh->prepare("SELECT * from
$st->execute();
Murali Mani
studentTemp
. ", " .
. ")");
("error inserting
studentTemp");
Perl with HTML forms (contd..)
print ("<table border=1>\n");
print ("<tr><th>number</th><th>name</th></tr>\n");
while ($data = $st->fetchrow_hashref()) {
print "<tr><td> $data->{NUM} </td><td> $data->{NAME}
</td></tr>\n";
}
print ("</table>\n");
print <<ENDHTML;
<br><br>
Num: <input type="text" name="a1"><br>
Name: <input type="text" name="a2"><br><br>
<input type="Submit" name="submit" value="Enter
Information"/>
ENDHTML
print ("</form></body></html>\n");
$st->finish(); $dbh->disconnect();
Murali Mani
Java Servlets

Steps
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Install a web server, such as Apache Tomcat
Learn about servlets
Learn about HTML forms
Learn how to use JDBC
Integrate them into your project.
Murali Mani
Installing a web server
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
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Download it from jakarta.apache.org/tomcat
You might need about 50 MB of space for the
installation
For example, get the .tar.gz file (You may
want to keep it in the temp directory, rather
than your personal disk space).
tar –xvzf file.tar.gz (untar it directly without
unzipping it to save space).
Murali Mani
Setting up the webserver
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I will call the root of the installation $TOMCAT_DIR
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Check the file $TOMCAT_DIR/conf/server.xml
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In your .cshrc
setenv TOMCAT_DIR /home/mmani/jakarta-tomcat-5.0.18
You will see a line <Connector port=“8080”
You can renumber the port, say between 1200 and 20000
For your .cshrc


setenv PATH ${PATH}:${TOMCAT_DIR}/bin
setenv CLASSPATH
${CLASSPATH}:${TOMCAT_DIR}/common/lib/servletapi.jar
Murali Mani
Test the webserver
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Run the script startup.sh
Open the page: http://ccc2.wpi.edu:1200
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You ran the startup.sh from ccc2
Your web server is configured to port 1200
(default was 8080)
To check for errors etc, check
$TOMCAT_DIR/logs
To shut down, run the script shutdown.sh
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
Check what processes are running: ps -u mmani
Kill unnecessary Java processes: killall java
Murali Mani
Servlets: Introduction
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Write the java code, and compile it.
Configure the web server to recognize the
servlet class.
Restart the web server
Murali Mani
First Java Servlet
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Check the directory
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$TOMCAT_DIR/webapps/servletsexamples/WEB-INF/classes
There exist example servlets here
Create a test servlet with the method doGet
Compile it, let our test servlet be
TestServlet.class
Murali Mani
Configuring the web server

Check $TOMCAT_DIR/webapps/servletsexamples/WEB-INF/web.xml

Add the declarations
<servlet>
<servlet-name>MyTestServlet</servlet-name>
<servlet-class>TestServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>MyTestServlet</servlet-name>
<url-pattern>/servlet/FirstTestServlet</url-pattern>
</servlet-mapping>
Murali Mani
Test the servlet


Restart the web server
Go to the URL
http://ccc2.wpi.edu:1200/servlets-examples/servlet/FirstTestServlet
Murali Mani
JDBC: CLI (Call Level
Interface)
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JDBC (Java Database Connetivity) is a
standard API for connecting to databases
from Java programs (such as servlets).
Different vendors provide JDBC drivers
implementing the JDBC API for different
DBMS: Oracle, mySQL etc
Murali Mani
Java Code with JDBC

Steps
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import java.sql.*
Load a driver instance
Establish Connection
Create a Statement
Query
Murali Mani
JDBC with Oracle
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JDBC driver comes with database server
Check $ORACLE_HOME/jdbc/Readme.txt
setenv CLASSPATH
${CLASSPATH}:${ORACLE_HOME}/jdbc/lib/
ojdbc6.jar
Murali Mani
JDBC: Oracle

Loading a Driver
Class.forName (“oracle.jdbc.driver.OracleDriver”);

Establishing a Connection
Connection conn =
DriverManager.getConnection(“jdbc:oracle:thin:@
oracle.wpi.edu:1521:WPIDBR2”, <userName>,
<password>);

Create a Statement
Statement stmt = conn.createStatement ();
Murali Mani
JDBC with mySQL


You need to install the driver mySQL
Connector/J from www.mysql.com
Setenv CLASSPATH <dir>/mysql-connectorjava-3.1.0-stable-bin.jar
Murali Mani
JDBC: mySQL

Loading a Driver
Class.forName (“com.mysql.jdbc.Driver”);

Establishing a Connection
Connection conn = DriverManager.getConnection
(“jdbc:mysql://mysql.wpi.edu/<dbName>”,
<userName>, <password>);

Create a Statement
Statement stmt = conn.createStatement ();
Murali Mani
Queries using JDBC

Queries: SQL DDL
String sql = “CREATE TABLE a (a1 int, a2 int)”;
stmt.executeUpdate (sql)

Queries: SQL DML (Updates)
String sql = “INSERT INTO a values (1, 1)”;
stmt.executeUpdate (sql)

Queries: SQL DML (Retrieval)
String sql = “SELECT * FROM a”;
ResultSet r = stmt.executeQuery (sql);
Murali Mani
JDBC Result Set: Iteration

We can iterate over a result set, r as:
/* fetch the next tuple from r and ensure that it is not
empty */
while (r.next ()) {
System.out.println (“a1 = “ + r.getString (“a1”));
}
Murali Mani
Close the statement and
connection
try {
stmt.close ();
} catch (SQLException sqlEx) {
System.out.println (“Could not close statement:” +
sqlEx.toString ());
try {
conn.close ();
} catch (SQLException sqlEx) {
System.out.println (“Could not close connection:”
+ sqlEx.toString ());
Murali Mani
Using Servlets with JDBC

Ensure that the JDBC driver can be
downloaded by our servlet.

The servlet sees only the classes available at



$TOMCAT_DIR/shared/lib
$TOMCAT_DIR/common/lib
Create a symbolic link, for example, for
Oracle JDBC driver, from the directory
$TOMCAT_DIR/shared/lib
ln –s $ORACLE_HOME/jdbc/lib/ojdbc6.jar ojdbc6.jar
Murali Mani
Related documents
Introduction to Database Systems
Introduction to Database Systems
Data Modeling using XML Schemas
Data Modeling using XML Schemas
PowerPOINT
PowerPOINT
here - Carleton University
here - Carleton University
Presentation14
Presentation14
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