plug-in sounds a bit like this:
<ul>
 <li>given that database has an initialized data model (i.e. tables to hold stuff) </li>
    <li>and given the plug-in’s method is invoked with a dataset (i.e. rows for tables) </li>
     <li>when a select statement is issued for a value only found in the dataset inserted by the plug-in </li>
     <li> then the desired item (i.e. column value) should be returned </li>
</ul>
</p>

<p>
In essence, this story is the use case for the plug-in– reading it you can