add keywords during publishing

app/Models/Dataset.php

@@ -194,6 +194,11 @@ class Dataset extends Model
         return $this->hasMany(\App\Models\DatasetReference::class, 'document_id', 'id');
     }
 
+    public function subjects()
+    {
+        return $this->hasMany(\App\Models\Subject::class, 'document_id', 'id');
+    }
+
 
     /**
      * Get the xml-cache record associated with the dataset.

app/Models/Subject.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use App\Models\Dataset;
+
+class Subject extends Model
+{
+    protected $table = 'document_subjects';
+    public $timestamps = false;
+
+    protected $fillable = ['value', 'type'];
+
+    public function dataset()
+    {
+        return $this->belongsTo(Dataset::class, 'document_id', 'id');
+    }
+}

app/Models/XmlCache.php

@@ -14,7 +14,7 @@ class XmlCache extends Model
      * @var string
      */
     protected $table = 'document_xml_cache';
-    public $timestamps = false;   
+    public $timestamps = false;
 
 
     /**
@@ -56,14 +56,13 @@ class XmlCache extends Model
     }
 
     /**
-     * Check if a document in a specific xml version is already cached or not.
+     * Check if a dataset in a specific xml version is already cached or not.
      *
      * @param mixed $datasetId
-     * @param mixed $xmlVersion
      * @param mixed $serverDateModified
      * @return bool Returns true on cached hit else false.
      */
-    public function hasValidEntry($datasetId, $serverDateModified)
+    public function hasValidEntry($datasetId, $serverDateModified) : bool
     {
         $select = DB::table('document_xml_cache');
         $select->where('document_id', '=', $datasetId)