and send <BODY> # print start_html("Nile dot Com Title Update"); # # Verify the validity of the values from the form # $tid > 0 or later("Title ID must be a number greater than zero!"); $price > 0 or later("Price must be a number greater than zero!"); # # Attempt to load the driver and connect to the database # eval { $dbh = DBI->connect("DBI:$DB_type:test_nile", $DB_login, $DB_password); }; # # Check if the eval failed (driver failed to load) # if ($@) { die "Could not install driver ($DBI::err): $DBI::errstr\n"; } # # Check if the connection attempt was successful # defined($dbh) or die "Could not connect to db ($DBI::err): $DBI::errstr\n"; # # Check if the book is in the title table # in_table($dbh, $tid) or later("Title id \"$tid\" is not in the table!"); # # Prepare the following SQL statement and receive a statement handle # $sth = $dbh->prepare(qq{ UPDATE title SET price=$price WHERE title_id=$tid }) or die "Prepare of UPDATE: ", $dbh->errstr, "\n"; # # Execute the prepared SQL statement # $sth->execute or die "Execute of UPDATE: ", $dbh->errstr, "\n"; # # Check the return value from the UPDATE statement # $sth->rows == 0 and later("No rows were updated! Did you specify a correct title id?"); $sth->rows > 1 and later("Multiple rows were updated! How did that happen?"); # # We're done with this statement, free up the resources # $sth->finish; # # Disconnect from the database, we're done! # $dbh->disconnect or warn "Disconnect: ", $dbh->errstr, "\n"; # # Print out a nice big header, # print h1("Title Update"); print "Updating of title id $tid<br>"; print "New price of $price was successful.<br>"; # # Send </BODY></HTML> # print end_html; exit 0; # # This subroutine is used to cleanly exit the program, # sending proper HTML back to the browser # sub later { my( $goof ) = @_; # # Print out a nice big header, # print h1("Update Failed"); print $goof; # # Send </BODY></HTML> # print end_html; # # Disconnect from the database, we're done! # $dbh and $dbh->disconnect; exit 0; } # # This subroutine checks if a title is in the title table given its id number. # It returns the null string if the title is not in the table, # and the name of the book if it does exist. # sub in_table { my( $dbh, $tid ) = @_; my( $db_tid ); my( $sth ); # # Prepare the following SQL statement and receive a statement handle # $sth = $dbh->prepare(qq{ SELECT title_id FROM title WHERE title_id = $tid }) or die "Prepare of SELECT: ", $dbh->errstr, "\n"; # # Execute the prepared SQL statement # $sth->execute or die "Execution of SELECT: ", $dbh->errstr, "\n"; while (( $db_tid ) = $sth->fetchrow_array) { # # We're done with this statement, free up the resources # $sth->finish; return 1; } # # We're done with this statement, free up the resources # $sth->finish; return 0; }

#! /usr/local/bin/perl # Title Update Lab: Solution # # Begin loading the needed extensions # use DBI; # The DBI extension use CGI qw (:html2 :form); # The CGI extension use CGI::Carp qw (carpout); # The extra carping routine # # The file dbtype.pl sets a variable which determines the type of database # you will use. This file will be found in either /tmp or /temp. # use lib qw(/tmp /temp); require 'dbtype.pl'; # # Set the path, unbuffer STDOUT, and redirect errors to the browser # $ENV{PATH} = join ":", qw(/usr/bin /bin /sbin /usr/sbin /etc); $| = 1; carpout(\*STDOUT); # # Declare variables # my( $dbh, $rv, $sth ); my( $tid, $price ); # # Accept the CGI request # my( $q ) = new CGI; # # Read values from the form which called us # $price = $q->param("price") || 0; $tid = $q->param("title_id") || 0; # # Send the HTTP header # print $q->header; # # Set the and send <BODY> # print start_html("Nile dot Com Title Update"); # # Verify the validity of the values from the form # $tid > 0 or later("Title ID must be a number greater than zero!"); $price > 0 or later("Price must be a number greater than zero!"); # # Attempt to load the driver and connect to the database # eval { $dbh = DBI->connect("DBI:$DB_type:test_nile", $DB_login, $DB_password); }; # # Check if the eval failed (driver failed to load) # if ($@) { die "Could not install driver ($DBI::err): $DBI::errstr\n"; } # # Check if the connection attempt was successful # defined($dbh) or die "Could not connect to db ($DBI::err): $DBI::errstr\n"; # # Check if the book is in the title table # in_table($dbh, $tid) or later("Title id \"$tid\" is not in the table!"); # # Prepare the following SQL statement and receive a statement handle # $sth = $dbh->prepare(qq{ UPDATE title SET price=$price WHERE title_id=$tid }) or die "Prepare of UPDATE: ", $dbh->errstr, "\n"; # # Execute the prepared SQL statement # $sth->execute or die "Execute of UPDATE: ", $dbh->errstr, "\n"; # # Check the return value from the UPDATE statement # $sth->rows == 0 and later("No rows were updated! Did you specify a correct title id?"); $sth->rows > 1 and later("Multiple rows were updated! How did that happen?"); # # We're done with this statement, free up the resources # $sth->finish; # # Disconnect from the database, we're done! # $dbh->disconnect or warn "Disconnect: ", $dbh->errstr, "\n"; # # Print out a nice big header, # print h1("Title Update"); print "Updating of title id $tid<br>"; print "New price of $price was successful.<br>"; # # Send </BODY></HTML> # print end_html; exit 0; # # This subroutine is used to cleanly exit the program, # sending proper HTML back to the browser # sub later { my( $goof ) = @_; # # Print out a nice big header, # print h1("Update Failed"); print $goof; # # Send </BODY></HTML> # print end_html; # # Disconnect from the database, we're done! # $dbh and $dbh->disconnect; exit 0; } # # This subroutine checks if a title is in the title table given its id number. # It returns the null string if the title is not in the table, # and the name of the book if it does exist. # sub in_table { my( $dbh, $tid ) = @_; my( $db_tid ); my( $sth ); # # Prepare the following SQL statement and receive a statement handle # $sth = $dbh->prepare(qq{ SELECT title_id FROM title WHERE title_id = $tid }) or die "Prepare of SELECT: ", $dbh->errstr, "\n"; # # Execute the prepared SQL statement # $sth->execute or die "Execution of SELECT: ", $dbh->errstr, "\n"; while (( $db_tid ) = $sth->fetchrow_array) { # # We're done with this statement, free up the resources # $sth->finish; return 1; } # # We're done with this statement, free up the resources # $sth->finish; return 0; }