ActiveRecord,Querying and For Loops

djengineer · May 11, 2016, 2:35pm

Hi there!

I have a question about for loops and Active Record and querying.

I have this code below that uses id stored in session and it is used to query for the users’ first names.

$searchmodel= new User;

   //&#036;user1 is object from model with id from session


        &#036;user1 = &#036;searchmodel::findOne(&#036;session['user1']);


        &#036;usernames = &#036;user1-&gt;first_name.&quot;, &quot;;





      for(&#036;j='2';&#036;j&lt;='5';&#036;j++){


        &#036;thisuser = &#036;searchmodel::findOne(&#036;session['user'.&#036;j]);


        &#036;usernames .= &#036;thisuser-&gt;first_name.&quot;,&quot;;


      }

Problem:

The first half of the code is working, where it is able to get the first name and populate $usernames.

But the second half of the code, in the For Loop, $thisuser does not become an object, and i get the error of "Trying to get property of non-object".

      for(&#036;j='2';&#036;j&lt;='5';&#036;j++){


        &#036;thisuser = &#036;searchmodel::findOne(&#036;session['user'.&#036;j]);

//line below gets "Trying to get property of non-object" error

        &#036;usernames .= &#036;thisuser-&gt;first_name.&quot;,&quot;;


      }

I know that $session[‘user’.$j] works, and that the for loop works if i put in $session[‘user1’] instead. I’ve even tried re-initializing $thisuser in each loop, but there is no difference.

What am I missing?

I understand that putting it all into an array would be better than having 5 variables, but this might become a problem when i make the switch later on.

Thank you!!

patrickm · May 12, 2016, 3:02am

findOne returns null if it can not find a record:

http://www.yiiframework.com/doc-2.0/yii-db-baseactiverecord.html#findOne()-detail

Thus whatever “$session[‘user’ . $j]” returns, it is not a key found in the database.

djengineer · May 15, 2016, 6:55am

Thanks! Guess I will have to find a work around.

patrickm · May 15, 2016, 7:27am

Checking whether "$thisuser" is null before using it would be good practice.