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Php Delete From Db Tutorial


We will now use our users table inside the database examples:

users table

 

 

 

 

Our users table has 3 columns: id, name, surname.

To DELETE a row from a table we will:

  1. connect to the server (localhost)
  2. select a database (examples)
  3. create a SQL DELETE query
  4. run the query and store the result
  5. check if the query has been successful
<?php #deleteData.php
//connecting to server
$dbc = mysqli_connect('localhost','root','') or
die('could not connect: '. mysqli_connect_error() );

//selecting the database
mysqli_select_db("examples") or die('could not select db');

// OLD DATA: SUPPOSE WE HAVE A ROW WITH...
/*
id = 15;
name = "jane";
* surname = "doe";

*/


// AND WE WANT TO DELETE IT
//THE ID OF THE ROW TO DELETE
  $delete_id = 15;

//CREATING A DELETE QUERY (use LIMIT to be sure you delete only that row )
/*
* DELETE FROM
`DB`.`TABLE` WHERE `TABLE`.`FIELD` = value LIMIT 1 ;
*/

$q = "
DELETE FROM `examples`.`users` WHERE `users`.`id`= '$delete_id' LIMIT 1 ";

//EXECUTING THE QUERY AND STORING THE RESULT IN A VARIABLE
$result = mysqli_query($dbc, $q);

//CHECKING IF THE QUERY AFFECTED A ROW USING mysqli_affected_rows()
if(mysqli_affected_rows($dbc) == 1 ){
//positive response
echo "user deleted";
} else {
//negative response
echo "could not delete user";
}

//CLOSING DATABASE CONNECTION
mysqli_close($dbc);
?>

PLEASE NOTE: the DELETE command is quite powerful, if you do not specify which row you want to delete, ALL the rows will be deleted. That's why you should always use a WHERE clause.


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