undefined method `destroy' for nil:NilClass - ruby-on-rails

Question

My app successfully creates rows for a table every time a user submits some stats. Now I want to provide a delete button to be able to delete some rows.
When I click the delete button I get the error:
undefined method `destroy' for nil:NilClass
Seems like either rails doesn't understand the destroy method in this case for whatever reason, or rails doesn't see anything to destroy, hence the nil:NilClass.
My first question is in identifying which is the case, if either of those.
My second question is fixing it :D
Here's my show.html:
<% provide(:title, "Log" ) %>
<% provide(:heading, "Your Progress Log") %>
<div class="row">
<div class="span8">
<% if #user.status_update.any? %>
<h3>Status Updates (<%= #user.status_update.count %>)</h3>
<table>
<thead>
<tr>
<th>Entry Date</th>
<th>Weight</th>
<th>BF %</th>
<th>LBM</th>
<th>Fat</th>
<th>Weight Change</th>
<th>BF % Change</th>
<th>Fat Change</th>
</tr>
</thead>
<tbody class = "status updates">
<%= render #status_updates %>
</tbody>
<% end %>
</div>
</div>
The "<%= render #status_updates %>" calls the _status_update partial.
<tr>
.
.
.
.
<% if current_user==(status_update.user) %>
<td>
<%= link_to "delete", status_update, method: :delete %>
</td>
<% end %>
</tr>
And then finally, here is the StatusUpdateController
def destroy
#status_update.destroy
redirect_to root_url
end
Here are the parameters on the error page:
{"_method"=>"delete",
"authenticity_token"=>"w9eYIUEd2taghvzlo7p3uw0vdOZIVsZ1zYIBxgfBymw=",
"id"=>"106"}

Answer 1

As you are not showing any code (filters or so) that could assign #status_update, I assume there is none. So, the instance variable #status_update in your in your destroy method is not set. You need to query the class with the object's ID.
Rewrite your destroy method as follows:
def destroy
#status_update = StatusUpdate.find(params[:id])
if #status_update.present?
#status_update.destroy
end
redirect_to root_url
end
Note: Replace the classname StatusUpdate with your actual class name.