foreach $line (<FILE>) 
         {
           chomp $_;
[download]

#$dbh->do('DROP TABLE test1'); # uncomment after first run
my $sql = 'CREATE TABLE test1 (
             type     char(5),
             students int, 
             class    int, 
             teachers int, 
             hostel   char(10) )';
             
$dbh->do($sql);
my $sqli = 'INSERT INTO test1 VALUES (?,?,?,?,?)';
my $sth = $dbh->prepare($sqli);

# 1 records
my @fld=();

# read data
foreach (<DATA>) {
  chomp $_;
  my ($event,$data)=split(/:/,$_);
  
  if ($event =~ /\(B\)/){
     insert_record() if ($fld[0]);
     $fld[0] = "BOYS";
  }
  
  if( $event =~ /\(G\)/){
     insert_record() if ($fld[0]);
     $fld[0] = "GIRLS";
  }

  if ($event =~ /^No.of stud/i){
    $fld[1] = $data;
  }

  if($event =~ /^No.of class/i){
    $fld[2] = $data;
  }

  if($event =~ /^No.of teach/i){
    $fld[3] = $data;
  }

  if($event =~ /^Hostel facility/i){
    $fld[4] = $data;
  }
}
# don't forget last record
insert_record() if ($fld[0]); 

# insert one records
sub insert_record {
  print "Inserting @fld\n";
  $sth->execute(@fld[0..4]);
  @fld=();
}

__DATA__
+++++++++++School(B):Students++++++++++
No.of students:120
No.of classes:2
No.of teachers:5
Hostel facility:available
++++++++++School(G):Students+++++++++++
No.of students:300
No.of classes:3
No.of teachers:10
[download]

Here is another approach, by using the file record separator ($/) to actually a "record" in your data file. There are a few approaches to it, one approach requires to change the source data file to use two newlines between records; this is because $/ can't take a regex as input.

When $/ value is an empty string it will match \n\n+ or a paragraph.

Also, if you use a hash to generate a table to translate the description to the field number you can simply the script for maintaning and when adding/removing fields as well as generating a template in case your need to feed default values.

Disclosure: I don't have a SQL server to test the code, that's why I commented the code, I focused the attention on how the data is handled.

#!/usr/bin/perl

use warnings;
use strict;

my %fields = (
    'Type'              => 0,
    'No.of students'    => 1,
    'No.of classes'     => 2,
    'No.of teachers'    => 3,
    'Hostel facility'   => 4,
);


my $dbh;
#$dbh->do('DROP TABLE test1'); # uncomment after first run
#my $sql = 'CREATE TABLE test1 (
#             type     char(5),
#             students int, 
#             class    int, 
#             teachers int, 
#             hostel   char(10) )';
             
#$dbh->do($sql);
my $sqli = 'INSERT INTO test1 VALUES (?,?,?,?,?)';
#my $sth = $dbh->prepare($sqli);

my @record = ();

local $/ = "";
foreach(<DATA>) {
    chomp;
    # Fix the type field
    if(!s/^\++School\(B\):Students\++/Type:BOYS/) {
        s/^\++School\(G\):Students\++/Type:GIRLS/;
    }
    my @arr = split /[\r\n]+/;
    foreach(@arr) {
        my ($key, $data) = split /\s*:\s*/;
        $record[$fields{$key}] = $data;
    }
    print "Inserting \"@record\"\n";
#    $sth->execute(@record[0..4]);
}

__DATA__
+++++++++++School(B):Students+++++++++++
No.of students : 120
No.of classes:2
No.of teachers:5
Hostel facility:available

+++++++++++School(G):Students+++++++++++
No.of students:300
No.of classes:3
No.of teachers:10
[download]

Your script works fine except because the second record does not have a Hostel facility field, it uses the data from the previous record

c:\Temp\perlmonks>perl 919135.pl
Inserting "BOYS 120 2 5 available"
Inserting "GIRLS 300 3 10 available"
[download]

Just need to clear the @record after the execute with

@record=();
[download]

poj