Here is the code that I've used
html:
<form action = 'insert.php' method='POST'>
<input type = "text" name = "name">
<input type = "submit" name = "submit">
</form>
php:
<?php
$servername='localhost';
$username='noob';
$password='password';
$conn = mysqli_connect($servername, $username, $password);
if (!$conn)
die("Connection failed: " . mysqli_connect_error());
$a=$_POST['name'];
mysqli_query("INSERT INTO table1 (name) VALUES ('$a')");
?>
Right now, the code above inserts a name into a table called table 1. My question now is, say I input many names into the table, but I want each name to have a unique 6 character/digit id. How would I change this code? For example, after 3 inserts, the table should look like this:
[table 1]
name unique_id
NAME1 994323
NAME2 832344
NAME3 332123
Each value of unique_id must be unique. Is there any efficient way to do this?
For the random code generation you can use RAND() as To obtain a random integer N in the range a <= N < b, just use the expression FLOOR(a + RAND() * (b – a)) as described in mysql docs
Your query is vulnerable to SQL Injection, fix it with mysqli_real_escape_string !
$name = mysqli_real_escape_string($_POST['name']);
$result = mysqli_query("SELECT FLOOR(100000 + RAND() * 990000) AS random_num
FROM table1
WHERE random_num NOT IN (SELECT table1.code FROM table1)
LIMIT 1");
$row = mysqli_fetch_row($result);
$code = $row[0];
mysqli_query("INSERT INTO table1 (name, code) VALUES ('$name', '$code')");
This is the working query for random digit generation: http://sqlfiddle.com/#!9/2acd3/1
EDIT:
Personally I prefer PDO instead of mysqli functions, anyway,
someone asked my why I suggest the PDO instead of MySQLi function. This is the way that I suggested, You can use whatever you want
Database Support
API
Named parameters
Prepared statements (client side)
Well you can use timestamp which is unique but its not 6 digit rather its more than that .For this to work you have to use varchar as column data type and use php function time(). This will generate unique digit.For this increase your column length to apprx 15.