Delete More Records through check box?

ob_start();
$host="localhost"; // Host name
$username="root"; // Mysql username
$password=""; // Mysql password
$db_name="cms"; // Database name
//$tbl_name="test_mysql"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

// Select data from table..
$sql="SELECT * FROM data";
$result=mysql_query($sql);
extract($_POST);

$count =mysql_num_rows($result);

// Check if delete button active, start this
if(isset($_POST['delete'])){
    for($i=0;$i<$count;$i++){
        $del_id = $checkbox[$i];
        $sql = "DELETE FROM data WHERE id='$del_id'";
        $reslt = mysql_query($sql);
    }   
    // if successful redirect to delete_multiple.php
    if($reslt){
        header("location:deletemorerecords.php");
       
    }
}
mysql_close();
?>

PHP Login script tutorial..

Overview

In this tutorial create 3 files 1. main_login.php 2. checklogin.php 3. login_success.php Step 1. Create table "members" in database "test". 2. Create file main_login.php. 3. Create file checklogin.php. 4. Create file login_success.php. 5. Create file logout.php  ------------------------------------------------------------------- 1. Create table "members" CREATE TABLE `members` ( `id` int(4) NOT NULL auto_increment, `username` varchar(65) NOT NULL default '', `password` varchar(65) NOT NULL default '', PRIMARY KEY (`id`) ) TYPE=MyISAM AUTO_INCREMENT=2 ; -- -- Dumping data for table `members` -- INSERT INTO `members` VALUES (1, 'jasim', '1234'); ------------------------------------------------------------- 2. Create file main_login.php Member Login Username : Password :     ------------------------------------------------------------------------------------- 3. Create file checklogin.php $host="localhost"; // Host name $username=""; // Mysql username $password=""; // Mysql password $db_name="test"; // Database name $tbl_name="members"; // Table name // Connect to server and select databse. mysql_connect("$host", "$username", "$password")or die("cannot connect"); mysql_select_db("$db_name")or die("cannot select DB"); // username and password sent from form $myusername=$_POST['myusername']; $mypassword=$_POST['mypassword']; // To protect MySQL injection (more detail about MySQL injection) $myusername = stripslashes($myusername); $mypassword = stripslashes($mypassword); $myusername = mysql_real_escape_string($myusername); $mypassword = mysql_real_escape_string($mypassword); $sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'"; $result=mysql_query($sql); // Mysql_num_row is counting table row $count=mysql_num_rows($result); // If result matched $myusername and $mypassword, table row must be 1 row if($count==1){ // Register $myusername, $mypassword and redirect to file "login_success.php" session_register("myusername"); session_register("mypassword"); header("location:login_success.php"); } else { echo "Wrong Username or Password"; } ?> 4.Create file login_success.php // Check if session is not registered , redirect back to main page. // Put this code in first line of web page. session_start(); if(!session_is_registered(myusername)){ header("location:main_login.php"); } ?> Login Successful 5. Logout.php If you want to logout, create this file // Put this code in first line of web page. session_start(); session_destroy(); ?>

What are the difference between DDL, DML and DCL commands?

DDL

Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples:

• CREATE - to create objects in the database
• ALTER - alters the structure of the database
• DROP - delete objects from the database
• TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed
• COMMENT - add comments to the data dictionary
• RENAME - rename an object

DML

Data Manipulation Language (DML) statements are used for managing data within schema objects. Some examples:

• SELECT - retrieve data from the a database
• INSERT - insert data into a table
• UPDATE - updates existing data within a table
• DELETE - deletes all records from a table, the space for the records remain
• MERGE - UPSERT operation (insert or update)
• CALL - call a PL/SQL or Java subprogram
• EXPLAIN PLAN - explain access path to data
• LOCK TABLE - control concurrency

DCL

Data Control Language (DCL) statements. Some examples:

• GRANT - gives user's access privileges to database
• REVOKE - withdraw access privileges given with the GRANT command

TCL

Transaction Control (TCL) statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.

• COMMIT - save work done
• SAVEPOINT - identify a point in a transaction to which you can later roll back
• ROLLBACK - restore database to original since the last COMMIT
• SET TRANSACTION - Change transaction options like isolation level and what rollback segment to use