diff --git a/app/Http/Controllers/Api/AssetModelsController.php b/app/Http/Controllers/Api/AssetModelsController.php
index 1eb206d219..d283486a6e 100644
--- a/app/Http/Controllers/Api/AssetModelsController.php
+++ b/app/Http/Controllers/Api/AssetModelsController.php
@@ -148,6 +148,11 @@ class AssetModelsController extends Controller
         $this->authorize('delete', AssetModel::class);
         $assetmodel = AssetModel::findOrFail($id);
         $this->authorize('delete', $assetmodel);
+
+        if ($assetmodel->assets()->count() > 0) {
+            return response()->json(Helper::formatStandardApiResponse('error', null,  trans('admin/models/message.assoc_users')));
+        }
+
         $assetmodel->delete();
         return response()->json(Helper::formatStandardApiResponse('success', null,  trans('admin/assetmodels/message.delete.success')));
 
diff --git a/app/Http/Controllers/Api/CategoriesController.php b/app/Http/Controllers/Api/CategoriesController.php
index 4be6eb4ed1..f299d09e92 100644
--- a/app/Http/Controllers/Api/CategoriesController.php
+++ b/app/Http/Controllers/Api/CategoriesController.php
@@ -113,7 +113,16 @@ class CategoriesController extends Controller
     {
         $this->authorize('delete', Category::class);
         $category = Category::findOrFail($id);
-        $this->authorize('delete', $category);
+
+        if ($category->has_models() > 0) {
+            return response()->json(Helper::formatStandardApiResponse('error', null,  trans('admin/categories/message.assoc_items', ['asset_type'=>'model'])));
+        } elseif ($category->accessories()->count() > 0) {
+            return response()->json(Helper::formatStandardApiResponse('error', null,  trans('admin/categories/message.assoc_items', ['asset_type'=>'accessory'])));
+        } elseif ($category->consumables()->count() > 0) {
+            return response()->json(Helper::formatStandardApiResponse('error', null,  trans('admin/categories/message.assoc_items', ['asset_type'=>'consumable'])));
+        } elseif ($category->components()->count() > 0) {
+            return response()->json(Helper::formatStandardApiResponse('error', null,  trans('admin/categories/message.assoc_items', ['asset_type'=>'component'])));
+        }
         $category->delete();
         return response()->json(Helper::formatStandardApiResponse('success', null,  trans('admin/categories/message.delete.success')));
 
diff --git a/app/Http/Controllers/Api/CompaniesController.php b/app/Http/Controllers/Api/CompaniesController.php
index 63048f3ba1..ee63e34b0a 100644
--- a/app/Http/Controllers/Api/CompaniesController.php
+++ b/app/Http/Controllers/Api/CompaniesController.php
@@ -117,9 +117,24 @@ class CompaniesController extends Controller
        $this->authorize('delete', Company::class);
        $company = Company::findOrFail($id);
             $this->authorize('delete', $company);
+
+        try {
             $company->delete();
             return response()
                 ->json(Helper::formatStandardApiResponse('success', null,  trans('admin/companies/message.delete.success')));
+        } catch (\Illuminate\Database\QueryException $exception) {
+            /*
+                 * NOTE: This happens when there's a foreign key constraint violation
+                 * For example when rows in other tables are referencing this company
+                 */
+            if ($exception->getCode() == 23000) {
+                return response()
+                    ->json(Helper::formatStandardApiResponse('error', null,  trans('admin/companies/message.assoc_users')));
+
+            } else {
+                throw $exception;
+            }
+        }
 
     }
 }
diff --git a/app/Http/Controllers/Api/CustomFieldsController.php b/app/Http/Controllers/Api/CustomFieldsController.php
index 7a4fa59345..2cae7e1af1 100644
--- a/app/Http/Controllers/Api/CustomFieldsController.php
+++ b/app/Http/Controllers/Api/CustomFieldsController.php
@@ -35,4 +35,26 @@ class CustomFieldsController extends Controller
         return $fieldset->fields()->sync($fields);
 
     }
+
+
+    /**
+     * Delete a custom field.
+     *
+     * @author [Brady Wetherington] [<uberbrady@gmail.com>]
+     * @since [v1.8]
+     * @return Redirect
+     */
+    public function destroy($field_id)
+    {
+        $field = CustomField::find($field_id);
+
+        if ($field->fieldset->count() >0) {
+            return response()->json(Helper::formatStandardApiResponse('error', null, 'Field is in use.'));
+        } else {
+            $field->delete();
+            return response()->json(Helper::formatStandardApiResponse('success', null,  trans('admin/custom_fields/message.field.delete.success')));
+
+        }
+    }
+
 }
diff --git a/app/Http/Controllers/Api/DepreciationsController.php b/app/Http/Controllers/Api/DepreciationsController.php
index 30ef61bc67..f8643f9d9c 100644
--- a/app/Http/Controllers/Api/DepreciationsController.php
+++ b/app/Http/Controllers/Api/DepreciationsController.php
@@ -6,8 +6,7 @@ use Illuminate\Http\Request;
 use App\Http\Controllers\Controller;
 use App\Helpers\Helper;
 use App\Models\Depreciation;
-use App\Models\Asset;
-use App\Http\Transformers\DatatablesTransformer;
+use App\Http\Transformers\DepreciationsTransformer;
 
 class DepreciationsController extends Controller
 {
@@ -23,7 +22,7 @@ class DepreciationsController extends Controller
         $this->authorize('view', Depreciation::class);
         $allowed_columns = ['id','name','created_at'];
 
-        $depreciations = Depreciation::select('id','name','months');
+        $depreciations = Depreciation::select('id','name','months','user_id','created_at','updated_at');
 
         if ($request->has('search')) {
             $depreciations = $depreciations->TextSearch($request->input('search'));
@@ -37,7 +36,7 @@ class DepreciationsController extends Controller
 
         $total = $depreciations->count();
         $depreciations = $depreciations->skip($offset)->take($limit)->get();
-        return (new DatatablesTransformer)->transformDatatables($depreciations, $total);
+        return (new DepreciationsTransformer)->transformDepreciations($depreciations, $total);
     }
 
 
@@ -74,7 +73,7 @@ class DepreciationsController extends Controller
     {
         $this->authorize('view', Depreciation::class);
         $depreciation = Depreciation::findOrFail($id);
-        return $depreciation;
+        return (new DepreciationsTransformer)->transformDepreciation($depreciation);
     }
 
 
@@ -113,6 +112,11 @@ class DepreciationsController extends Controller
         $this->authorize('delete', Depreciation::class);
         $depreciation = Depreciation::findOrFail($id);
         $this->authorize('delete', $depreciation);
+
+        if ($depreciation->has_models() > 0) {
+            return response()->json(Helper::formatStandardApiResponse('error', trans('admin/depreciations/message.assoc_users')));
+        }
+
         $depreciation->delete();
         return response()->json(Helper::formatStandardApiResponse('success', null,  trans('admin/depreciations/message.delete.success')));
 
diff --git a/app/Http/Transformers/DepreciationsTransformer.php b/app/Http/Transformers/DepreciationsTransformer.php
new file mode 100644
index 0000000000..be2c431722
--- /dev/null
+++ b/app/Http/Transformers/DepreciationsTransformer.php
@@ -0,0 +1,43 @@
+<?php
+namespace App\Http\Transformers;
+
+use App\Models\Depreciation;
+use Illuminate\Database\Eloquent\Collection;
+use Gate;
+use App\Helpers\Helper;
+
+class DepreciationsTransformer
+{
+
+    public function transformDepreciations (Collection $depreciations)
+    {
+        $array = array();
+        foreach ($depreciations as $depreciation) {
+            $array[] = self::transformDepreciation($depreciation);
+        }
+        return (new DatatablesTransformer)->transformDatatables($array);
+    }
+
+    public function transformDepreciation (Depreciation $depreciation)
+    {
+        $array = [
+            'id' => e($depreciation->id),
+            'name' => e($depreciation->name),
+            'months' => $depreciation->months . ' '. trans('general.months'),
+            'created_at' => Helper::getFormattedDateObject($depreciation->created_at, 'datetime'),
+            'updated_at' => Helper::getFormattedDateObject($depreciation->updated_at, 'datetime'),
+        ];
+
+        $permissions_array['available_actions'] = [
+            'update' => Gate::allows('update', Depreciation::class) ? true : false,
+            'delete' => Gate::allows('delete', Depreciation::class) ? true : false,
+        ];
+
+        $array += $permissions_array;
+
+        return $array;
+    }
+
+
+
+}