Show messages, when an element can not be deleted.

Fixes issue #43.

src/Entity/Attachments/AttachmentType.php

@@ -91,7 +91,7 @@ class AttachmentType extends AbstractStructuralDBElement
      */
     public function getAttachmentsForType(): Collection
     {
-        return $this->attachments;
+        return $this->attachments_with_type;
     }
 
     /**

src/Entity/PriceInformations/Currency.php

@@ -45,6 +45,7 @@ namespace App\Entity\PriceInformations;
 use App\Entity\Attachments\CurrencyAttachment;
 use App\Entity\Base\AbstractStructuralDBElement;
 use App\Entity\Parameters\CurrencyParameter;
+use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
@@ -103,6 +104,25 @@ class Currency extends AbstractStructuralDBElement
      */
     protected $parameters;
 
+    /** @var Collection<int, Pricedetail>
+     * @ORM\OneToMany(targetEntity="App\Entity\PriceInformations\Pricedetail", mappedBy="currency")
+     */
+    protected $pricedetails;
+
+    public function __construct()
+    {
+        $this->pricedetails = new ArrayCollection();
+        parent::__construct();
+    }
+
+    /**
+     * @return Collection
+     */
+    public function getPricedetails(): Collection
+    {
+        return $this->pricedetails;
+    }
+
     /**
      * Returns the 3 letter ISO code of this currency.
      *

src/Entity/PriceInformations/Pricedetail.php

@@ -82,7 +82,7 @@ class Pricedetail extends AbstractDBElement implements TimeStampableInterface
     /**
      * @var ?Currency The currency used for the current price information.
      *                If this is null, the global base unit is assumed.
-     * @ORM\ManyToOne(targetEntity="Currency")
+     * @ORM\ManyToOne(targetEntity="Currency", inversedBy="pricedetails")
      * @ORM\JoinColumn(name="id_currency", referencedColumnName="id", nullable=true)
      * @Selectable()
      */

src/Entity/UserSystem/Group.php

@@ -47,6 +47,7 @@ use App\Entity\Base\AbstractStructuralDBElement;
 use App\Entity\Parameters\GroupParameter;
 use App\Security\Interfaces\HasPermissionsInterface;
 use App\Validator\Constraints\ValidPermission;
+use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Validator\Constraints as Assert;
@@ -102,10 +103,12 @@ class Group extends AbstractStructuralDBElement implements HasPermissionsInterfa
      */
     protected $parameters;
 
+
     public function __construct()
     {
         parent::__construct();
         $this->permissions = new PermissionsEmbed();
+        $this->users = new ArrayCollection();
     }
 
     /**
@@ -136,4 +139,9 @@ class Group extends AbstractStructuralDBElement implements HasPermissionsInterfa
     {
         return $this->permissions;
     }
+
+    public function getUsers(): Collection
+    {
+        return $this->users;
+    }
 }