diff --git a/src/handlers/RecipeHandler.ts b/src/handlers/RecipeHandler.ts
index e90e951..99172eb 100644
--- a/src/handlers/RecipeHandler.ts
+++ b/src/handlers/RecipeHandler.ts
@@ -5,7 +5,6 @@ import { NotFoundError, ValidationError } from "../api/errors/httpErrors.js";
 import { RecipeInstructionStepDto } from "../api/dtos/RecipeInstructionStepDto.js";
 import { RecipeIngredientGroupDto } from "../api/dtos/RecipeIngredientGroupDto.js";
 import { RecipeIngredientDto } from "../api/dtos/RecipeIngredientDto.js";
-import { RecipeEntity } from "../entities/RecipeEntity.js";
 
 /**
  * Controls all recipe specific actions
@@ -26,8 +25,7 @@ export class RecipeHandler {
         if(recipeEntity === null){
             throw new NotFoundError("recipe with id " + id + " not found!")
         }
-        const recipeDto = this.mapper.toDto(recipeEntity);
-        return recipeDto;
+        return this.mapper.toDto(recipeEntity);
     }
 
     /**
@@ -39,26 +37,12 @@ export class RecipeHandler {
         if (!this.isRecipeDtoValid(dto)) {
             throw new ValidationError("recipe data is not valid!")
         }
-        var savedEntity: RecipeEntity;
         const recipeId = dto.id
         if(recipeId === undefined || recipeId.length === 0){
-            // create new recipe
-            const recipeEntity = this.mapper.toEntity(dto)
-            delete (recipeEntity as any).id;
-            savedEntity = await this.recipeRepository.create(recipeEntity);
+            return this.createRecipe(dto);
         } else {
-            // save existing Recipe
-            // First: Load current version of recipe from database
-            const recipeEntity = await this.recipeRepository.findById(recipeId);
-            if(!recipeEntity){
-                throw new ValidationError("No recipe with ID " + recipeId + " found in database!")
-            }
-            // merge changes into entity
-            this.mapper.mergeDtoIntoEntity(dto, recipeEntity);
-            // persist changes
-            savedEntity = await this.recipeRepository.update(recipeEntity);
+            return this.updateRecipe(dto);
         }
-        return this.mapper.toDto(savedEntity);
     }
     /**
      * Update recipe data
diff --git a/src/handlers/TagHandler.ts b/src/handlers/TagHandler.ts
index 1bcaca2..2c4a72e 100644
--- a/src/handlers/TagHandler.ts
+++ b/src/handlers/TagHandler.ts
@@ -1,6 +1,8 @@
 import { TagRepository } from "../repositories/TagRepository.js";
 import { TagDtoEntityMapper } from "../mappers/TagDtoEntityMapper.js";
 import { TagDto } from "../api/dtos/TagDto.js";
+import {UUID} from "crypto";
+import {ValidationError} from "../api/errors/httpErrors.js";
 
 /**
  * Handles business logic for tag operations.
@@ -63,7 +65,10 @@ export class TagHandler {
      *
      * @throws Error when the tag does not exist.
      */
-    async delete(id: string): Promise<void> {
+    async delete(id: UUID|string|undefined): Promise<void> {
+        if(!id){
+            throw new ValidationError("id is required for deleting tag");
+        }
         const existing = await this.tagRepository.findById(id);
         if (!existing) {
             throw new Error(`Tag with id ${id} not found`);
diff --git a/src/repositories/AbstractRepository.ts b/src/repositories/AbstractRepository.ts
index 1404e0a..632c952 100644
--- a/src/repositories/AbstractRepository.ts
+++ b/src/repositories/AbstractRepository.ts
@@ -1,6 +1,7 @@
 import { Repository, DeepPartial } from "typeorm";
 import { AppDataSource } from "../data-source.js";
 import { AbstractEntity } from "../entities/AbstractEntity.js";
+import {UUID} from "crypto";
 
 /**
  * Basic methods for saving, loading and deleting data
@@ -12,7 +13,7 @@ export abstract class AbstractRepository<T extends AbstractEntity> {
     this.repo = AppDataSource.getRepository(entity);
   }
 
-  async findById(id: string): Promise<T | null> {
+  async findById(id: string|UUID): Promise<T | null> {
     return this.repo.findOne({ where: { id } as any });
   }