input required depending on button of form - php

Question

To enter data into my database I created this form. The user can enter data add by clicking the add button the information is entered into the database. I am using required to force the user to enter text.
Now I added the edit and delete button. Therefore the user shall select a record with the radio buttons provided. But with the required in the input elements it is only possible to do edit or delete if text is entered.
Is it somehow possible to assign the required to a certain button?
<form>
<table>
<tr>
<td>
<input type="radio" name="aName" />
</td>
<td>a</td>
<td>record</td>
</tr>
<td>
<input type="radio" name="aName" />
</td>
<td>another</td>
<td>record</td>
</tr>
<tr>
<td></td>
<td>
<input type="text" placeholder="enter" required >
</td>
<td>
<input type="text" placeholder="something" required>
</td>
</tr>
</table>
<input type="submit" value="add" formaction="form1.php" formmethod="post"/>
<input type="submit" value="delete" formaction="form2.php" formmethod="post"/>
<input type="submit" value="edit" formaction="form3.php" formmethod="post"/>
</form>

Answer 1

A way to do this, is without using 'required', but reproducing this html5 effect using event handlers, focus() and alert().
event.preventDefault() prevents the form to submit.
Check it:
<form method="POST">
<table>
<tr>
<td>
<input type="radio" name="aName" />
</td>
<td>a</td>
<td>record</td>
</tr>
<td>
<input type="radio" name="aName" />
</td>
<td>another</td>
<td>record</td>
</tr>
<tr>
<td></td>
<td>
<input id="enter" type="text" placeholder="enter" >
</td>
<td>
<input id="something" type="text" placeholder="something" >
</td>
</tr>
</table>
<input id="add" formaction="form1.php" formmethod="post"
onclick="
if(document.getElementById('enter').value===''){
event.preventDefault();
document.getElementById('enter').focus();
alert('Please,fill out this field');
} else if(document.getElementById('something').value===''){
event.preventDefault();
document.getElementById('something').focus();
alert('Please,fill out this field');
}"
type="submit" value="add"/>
<input id="delete" type="submit" formaction="form2.php" formmethod="post value="delete"/>
<input id="edit" type="submit" formaction="form3.php" formmethod="post value="edit"/>
</form>