A Simple Login System with PHP & MySQL
Essential to any membership-based site is a long system. This code will provide you with the basis from which to start.
In MySQL, create a [users] table with 3 columns: login, password, last_logged_in. The last_logged_in column will store the time that the user last logged into the system.
// but for this code we'll manually create them
$username = "jim";
$password = "bob";
$sql="SELECT * FROM users WHERE login = '".$username."' AND password = '".$password."'";
// Execute the SQL statement
// results stored in the $rs variable.
$rs = mysql_query($sql);
// determine of the mysql_query() was successful
if(!$rs) {
$err=mysql_error();
print $err;
exit();
}
// If was successful, check returned result
// mysql_affected_rows() will return the number of rows affected
if(mysql_affected_rows()==0){
print "Username/password pair is invalid. Please try again.";
} else {
// display last logged in time
$row=mysql_fetch_array($r);
$last=$row["last_logged_in"];
print "Login successful. (You last logged in at ".$last.".)";
}
Of course, in real-world applications you won't want to store the password in plain text, but encrypt them with the PASSWORD function or a custom encryption method.
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