Introduction

The FTD (Flat Text Databases) is a term used to explain a plain text file used to create a database. A database is a
series of tables, each table containing a rows and columns. Applications of
databases are endless, one
example case would be an airline who needs to track flights, pilots, passengers, fuel trucks, etc. Using a database they
could easily manage to track all of this information and know at any time where a plane is, if it will have fuel when it
lands, how many passengers flew using first class and how many flew second class, and all other critical information.

There are many different types and sizes of databases. Small databases that only contain one table (series of
records) could be something small like a password database that links passwords to usernames. Larger databases, like the
airplane sample above, would have multiple crosslinked tables and could grow to be very large databases in comparison to a
table of passwords and usernames. Smaller databases generally use a simple format like the FTD, larger databases will
use formats like SQL (Structured Query Language) which allow far more features and expandability than the FTD.

Advantages and Disadvantages

FTD's are used in situations where a database server such as MySQL is too resource expensive and would generate far
too much
load overhead. An FTD uses very little resources when used for small databases and is very easy to maintain.

Using an FTD for a large database would become very slow however. An FTD is only useful for small, simple,
databases. In order to search and FTD you would need to individually check each record, in order to make this very fast and
efficient it would take a lot of work - this work is made simple in larger databases achieved through hashed searches done in
such packages as MySQL.

Implementation

In this demonstration there will be an html page that a visitor can enter the title of the book they want and will be
given information on that book. Users will also be able to browse all books in the database. The main file, ftd.pl,
demonstrates this.

To add an entry to our database, we simply append data in the format of "bookname:bookdata" to the flat text database.
To remove an entry, we remove the entry from the database.

Example Project: Bookstore

Get This Sample

View Live Sample

#!/usr/bin/perl

# TD July 1999
# ftd.pl
#

$datafile = "./ftddata";
&parse_form; # Standard TD form parsing routine

if ($ENV{'REQUEST_METHOD'} ne "POST") {
if ($ENV{'QUERY_STRING'} eq "") {
&print_form;
} else {
&print_all;
}

} else {
if ($FORM{'ACTION'} eq "Search") {
&read_data;
&print_html_head ("$FORM{'txtBook'}");
print "<H1>$FORM{'txtBook'}</H1>\n";
print "$BOOKS{$FORM{'txtBook'}}\n";
&print_html_tail;

} elsif ($FORM{'ACTION'} eq "Add") {
&add_data;

} else {
&print_html_head;
print "Action unknown!\n";
&print_html_tail;

}
}

sub add_data {
$a = "No Title Entered!";
$b = "No Text Entered!";

$a = $FORM{'txtTitle'} unless ($FORM{'txtTitle'} eq "");
$b = $FORM{'txtDesc'} unless ($FORM{'txtDesc'} eq "");
$bu = 1;

open (IN, "$datafile");
@data = <IN>;
close (IN);

foreach (@data) {
($xa,$xb) = split(/:/,$_);
if ($a eq $xa) { $Bu = 0; }
}

if ($Bu == 1) {
`echo \"$a:$b\" >> ./$datafile`;
&print_html_head("Added Book");
print "Added Book\n";
&print_html_tail;

} else {
&print_html_head("Could not add book");
print "Could not add data, book by that name already exists!\n";
&print_html_tail;

}
}

sub print_all {

&print_html_head ("Show All");

open (IN, "$datafile");
@data = <IN>;
close (IN);

foreach (@data) {
($a,$b) = split(/:/,$_);
print "<P><H3>$a</H3>\n$b</P>\n\n";
}

&print_html_tail;
}

sub read_data {
open (IN, "$datafile");
@data = <IN>;
close (IN);

foreach (@data) {
($a,$b) = split(/:/,$_);
$BOOKS{$a} = $b;
}
}

sub parse_form {
read(STDIN, $buffer, $ENV{CONTENT_LENGTH});
@pairs = split(/&/, $buffer);
foreach $pair (@pairs) {
($name, $val) = split(/=/, $pair);
$val =~ tr/+/ /;
$val =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
$FORM{$name} = $val;
}
}

sub print_form {

&print_html_head("FTD Sample");

print <<EOF;

<H1>Look up a book</H1>

<FORM METHOD=POST ACTION="./ftd.pl">
Book: <SELECT NAME="txtBook">
EOF

open (IN, "$datafile");
@data = <IN>;
close (IN);

foreach (@data) {
($a,$b) = split(/:/,$_);
print "<OPTION>$a</OPTION>\n";
}

print <<EOF;
</SELECT><BR>
<INPUT TYPE="SUBMIT" NAME="ACTION" VALUE="Search">
</FORM>
<BR><BR><H1>Add a book</H1>
<FORM METHOD=POST ACTION="./ftd.pl">
Title: <INPUT TYPE=TEXT NAME="txtTitle"><BR>
Description: <BR><TEXTAREA NAME="txtDesc" COLS=35 ROWS=8></TEXTAREA><BR>
<INPUT TYPE="SUBMIT" VALUE="Add" NAME="ACTION">
</FORM>

<BR>
Or you can <A HREF="./ftd.pl?all">browse all books</A>.
EOF

&print_html_tail;
}

sub print_html_head {
print <<EOF;
Content-type: text/html

<HTML>
<HEAD><TITLE>$_[0]</TITLE></HEAD>
<BODY>
EOF

}

sub print_html_tail {
print <<EOF;
</BODY>
</HTML>

EOF

}