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POPrevent duplicate records to a table using PHP
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  1. POPrevent duplicate records to a table using PHP
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    copied!<p>I want to prevent duplicate values into a database table from a form using PHP.</p> <p>I have created the following:</p> <p>A database with a table named <strong>clients</strong>:</p> <pre><code>CREATE TABLE clients( firstName varchar(20), lastName varchar(20), primary key(firstName, lastName)); </code></pre> <p>A simple form named <strong>form.html</strong></p> <pre><code>&lt;h2&gt;Enter your First and Last Name&lt;/h2&gt; &lt;form action="frm_script.php" method="post"&gt; &lt;p&gt;&lt;strong&gt;First Name:&lt;/strong&gt;&lt;br /&gt; &lt;input type="text" name="firstName" /&gt;&lt;/p&gt; &lt;p&gt;&lt;strong&gt;Last Name:&lt;/strong&gt;&lt;br /&gt; &lt;input type="text" name="lastName"/&gt;&lt;/p&gt; &lt;input type="submit" name="submit" value="Add Customer" /&gt; &lt;/form&gt; </code></pre> <p>A form processing script named <strong>frm_script.php</strong></p> <pre><code>&lt;?php if(isset($_POST['submit'])) { //get the name and comment entered by user $firstName = $_POST['firstName']; $lastName = $_POST['lastName']; //connect to the database $dbc = mysqli_connect('host', 'username', 'password', 'dbname') or die('Error connecting to MySQL server'); //insert results from the form input $query = "INSERT IGNORE INTO clients(firstName, lastName) VALUES('$firstName', '$lastName')"; $result = mysqli_query($dbc, $query) or die('Error querying database.'); mysqli_close($dbc); } echo "Customer Added"; ?&gt; </code></pre> <p>So far with my <strong>frm_script.php</strong> file the above works and for a unique record displays customer added. However, for a duplicate record it throws "Error Querying Database".</p> <p>How can I update the <strong>frm_script.php</strong> script for the following?</p> <p>If a duplicate row is found on entering a First / Last name combination it should display the message "Client already listed" along with that record.</p> <p>If no duplicate row is found on entering a First / Last name combination on the form it should insert the entry to the database and display the message "customer added"</p> <p>I have read that a SELECT should be run first then an INSERT but I am not sure how to implement this into my existing code.</p>
 

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