How to check on inserting new values if they already exists?
<p>I have a gridview and sqldatasource to bind data to gridview.</p>

<ul>
<li>I have 3 columns in database : Name,Age,Birthday.</li>
<li>I have 3 textboxes and a button for adding new row with values from
textboxes in the data table , gridview.</li>
</ul>

<p>When I click the button for adding a new row with those information , I need to check if the value from textbox for "Name" already exists in the data table in the column "Name" if yes then the update is canceled and the user is asked to enter another value.</p>
