Database Reference
In-Depth Information
{
print
$row
[
0
],
$cgi
->
br
();
}
$dbh
->
disconnect
();
# Print page trailer
print
$cgi
->
end_html
();
To try the script, install it in your
cgi-bin
directory and request it from your browser as
follows:
http://localhost/cgi-bin/show_tables_oo.pl
The script includes the CGI.pm module with a
use
CGI
statement, and then creates a
CGI
object,
$cgi
, through which it invokes the various HTML-generation calls.
head
er()
generates the
Content-Type:
header and
start_html()
produces the initial page
tags up through the opening
<body>
tag. After generating the first part of the page,
show_tables_oo.pl
retrieves and displays information from the server. Each table name
is followed by a
<br />
tag, produced by invoking the
br()
method.
end_html()
pro‐
duces the closing
</body>
and
</html>
tags.
CGI.pm calls often take multiple parameters, many of which are optional. To enable
you to specify just those parameters you need, CGI.pm understands
-name
=>
value
notation in parameter lists. For example, in the
start_html()
call, the
title
parameter
sets the page title. The
-name
=>
value
notation also permits parameters to be specified
in any order.
To use the CGI.pm function call interface rather than the object-oriented interface, write
scripts a little differently. The
use
line that references CGI.pm should import the method
names into your script's namespace so that you can invoke them directly as functions
without having to create a
CGI
object. For example, to import the most commonly used
methods, the script should include this statement:
use
CGI
qw(:standard)
;
The following script,
show_tables_fc.pl
, is the function call equivalent of the
show_tables_oo.pl
script just shown. It uses the same CGI.pm calls, but invokes them
as standalone functions rather than through a
$cgi
object:
#!/usr/bin/perl
# show_tables_fc.pl: Display names of tables in cookbook database
# (use the CGI.pm function-call interface)
use
strict
;
use
warnings
;
use
CGI
qw(:standard)
;
# import standard method names into script namespace
use
Cookbook
;
# Print header, blank line, and initial part of page
