- added nearly all migration files

- added nearly all database seed files

app/Http/Controllers/Frontend/SitelinkController.php

@@ -16,7 +16,9 @@ class SitelinkController extends Controller
             ->where('server_state', 'LIKE', "%" . $serverState . "%");
 
         $select
-            ->select(DB::raw('YEAR(server_date_published) as published_date'))
+            // ->select(DB::raw('EXTRACT(YEAR FROM server_date_published) as published_date'))
+            // ->select(DB::raw("DATE_PART('year', server_date_published) as published_date"))
+            ->select(DB::raw("YEAR(server_date_published) AS published_date"))
             ->distinct(true);
 
         $this->years = $select->pluck('published_date');

app/Http/Controllers/Oai/RequestController.php

@@ -148,7 +148,7 @@ class RequestController extends Controller
         $repositoryName = "RDR - Data Research Repository";
         $repIdentifier = "rdr.gba.ac.at";
         $sampleIdentifier = "oai:" . $repIdentifier . ":27";//$this->_configuration->getSampleIdentifier();
-        $earliestDateFromDb = Dataset::earliestPublicationDate();
+        $earliestDateFromDb = Dataset::earliestPublicationDate()->get('server_date_published');
 
         // set parameters for oai-pmh.xslt
         $this->_proc->setParameter('', 'email', $email);

app/Models/Dataset.php

@@ -258,11 +258,12 @@ class Dataset extends Model
         if (!$column) {
             $column = self::PUBLISHED_AT;
         }
-        return $query->whereNotNull('server_date_published')
+        return $query->select('server_date_published')
+            ->where('server_date_published', '<>', null)
             ->where('server_state', 'published')
             ->orderBy('server_date_published', 'asc')
-            ->first()
-            ->server_date_published;
+            ->first();
+            //->server_date_published;
     }
 
     public function setServerState($targetType)