SQL-PL Interface. Murali Mani. Perl /CGI with Oracle/mySQL Install your own web server and use servlets with JDBC and Oracle/mySQL

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1 SQL-PL Interface Some Possible Options Web Interface Perl /CGI with Oracle/mySQL Install your own web server and use servlets with JDBC and Oracle/mySQL Non-Web Interface JDBC with Oracle/mySQL Also other options like embedded SQL 1

2 Perl Features (from Mike Ciaraldi s slides) Created around 1987 by Larry Wall. A scripting language. Widely used. Utilities Web server programs (CGI). Quick reference to Perl 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"); 2

3 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 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"); } 3

4 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. How does Perl DBI work? (Image from OReilly) 4

5 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: $DBI::errstr"; Perl DBI (contd ) Note the usage of DBI->connect Also note configoracle.pm which looks like #!/usr/local/bin/perl package configoracle; use = = qw($host $sid $port $username $passwd); $host = "oracle.wpi.edu"; 5

6 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"). ")"); 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(); 6

7 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: $DBI::errstr"; Perl with HTML forms and Oracle #!/usr/local/bin/perl use CGI::Carp qw(fatalstobrowser warningstobrowser); use DBI; use configoracle; use CGI ":standard"; print "Content-type: text/html\n\n"; print ("<html><head><title>test Oracle - 2</title></head>\n"); print ("<body>\n"); print ('<form method=post action=testoracle2.pl>'); if ($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"; 7

8 Perl with HTML forms (contd..) if (defined (param ("submit"))) { $rows = $dbh->do ("INSERT INTO studenttemp VALUES (". $dbh->quote (param ("a1")). ", ". $dbh->quote (param ("a2")). ")"); if (! defined ($rows)) { print ("error inserting $DBI::errstr<br>\n"); } } $st = $dbh->prepare("select * from studenttemp"); $st->execute(); Perl with HTML forms (contd..) print ("<table border=1>\n"); print ("<tr><th>number</th><th>name</th></tr>\n"); while ($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(); 8

9 Java Servlets Steps 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. Installing a web server 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). 9

10 Setting up the webserver I will call the root of the installation $TOMCAT_DIR In your.cshrc setenv TOMCAT_DIR /home/mmani/jakarta-tomcat Check the file $TOMCAT_DIR/conf/server.xml You will see a line <Connector port= 8080 You can renumber the port, say between 1200 and For your.cshrc setenv PATH ${PATH}:${TOMCAT_DIR}/bin setenv CLASSPATH ${CLASSPATH}:${TOMCAT_DIR}/common/lib/servletapi.jar Test the webserver Run the script startup.sh Open the page: 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 Check what processes are running: ps -u mmani Kill unnecessary Java processes: killall java 10

11 Servlets: Introduction Write the java code, and compile it. Configure the web server to recognize the servlet class. Restart the web server First Java Servlet Check the directory $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 11

12 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> Test the servlet Restart the web server Go to the URL 12

13 JDBC: CLI (Call Level Interface) 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 Java Code with JDBC Steps import java.sql.* Load a driver instance Establish Connection Create a Statement Query 13

14 JDBC with Oracle JDBC driver comes with database server Check $ORACLE_HOME/jdbc/Readme.txt setenv CLASSPATH ${CLASSPATH}:${ORACLE_HOME}/jdbc/lib/ ojdbc6.jar 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 (); 14

15 JDBC with mysql You need to install the driver mysql Connector/J from Setenv CLASSPATH <dir>/mysql-connectorjava stable-bin.jar 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 (); 15

16 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); 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 )); 16

17 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 ()); 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 17

2. Follow the installation directions and install the server on ccc. 3. We will call the root of your installation as $TOMCAT_DIR

2. Follow the installation directions and install the server on ccc. 3. We will call the root of your installation as $TOMCAT_DIR Installing a Web Server 1. Install a sample web server, which supports Servlets/JSPs. A light weight web server is Apache Tomcat server. You can get the server from http://tomcat.apache.org/ 2. Follow