Perl / PHP MySQL
Difference between mysql_connect() and mysql_pconnect()
mysql_connect() and mysql_pconnect() both are working for database connection but with little difference. In mysql_pconnect(), ‘p’ stands for persistance connection.
When we are using mysql_connect() function, every time it is opening and closing the database connection, depending on the request .
But in case of mysql_pconnect() function,
First, when connecting, the function would try to find a (persistent) connection that’s already open with the same host, username and password. If one is found, an identifier for it will be returned instead of opening a new connection.
Second, the connection to the SQL server will not be closed when the execution of the script ends. Instead, the connection will remain open for future use (mysql_close() will not close connection established by mysql_pconnect()).
mysql_pconncet() is useful when you have a lot of traffice on your site. At that time for every request it will not open a connection but will take it from the pool. This will increase the efficiency of your site. But for general use mysql_connect() is best.
########################################################################
#################PERL SCRIPT TO UPDATE DATABASE#####################
########################################################################
vi UPDATEDB.pl
#!/usr/bin/perl
use DBI; # This must be import to connect to database
$user=”root”; # This is User ID of database
$password=”dialnet”; # This is the Password for Database
#The following lines is to create and open a handle to Connect the database “TEST” and #if unable to connect thro error msg
my $dbh = DBI->connect(“dbi:mysql:test”, $user, $password) or die “Could not Connect to Database”. DBI->errstr;
#Here I am preparing the statement to execute
my $sth=$dbh->prepare(<<SQL);
update user set validity_status=’USED’ where end_date<CURRENT_DATE();
SQL
#Here I am executing the statement
$sth->execute;
#Closing the Database Handle which is very Important
$dbh->disconnect;
Making the perl file UPDATEDB.pl executable using the following command chmod 700 UPDATEDB.pl
to execute the file type ./UPDATEDB.pl