Hibernate：在更新父实体的同时更新子实体？

Question

I have the following entities with a proper mapping and can create records properly by child entities. For example, when creating a Recipe, I can add Ingredients to this recipe and just save this recipe via its entity. Then recipe is created with its ingredients properly.

Now I need to update the Recipe and at this stage I am not sure what is the most proper way in Hibernate to update child record. I set the Recipe fields by request, but what should I do if the original Recipe has 3 ingredients (let's say IngA, IngB, IngC) and the updated ingredient has same and different ingredients (let's sat IngA, IngX, IngY).

At this stage, should I remove all the ingredients belonging to the Recipe and then add all the ingredients coming from update request?

Or how should I treat the child data for update?

Here is my update method which needs to be completed:

public void update(RecipeRequest request) {
    final Recipe recipe = recipeRepository.findById(request.getId())
            .orElseThrow(() -> new NoSuchElementFoundException(NOT_FOUND_RECIPE));
    recipe.setTitle(capitalizeFully(request.getTitle()));

    request.getRecipeIngredients().stream()
            .forEach(recipeIngredient -> {
                // get each of the requested ingredients
                final Ingredient ingredient = ingredientRepository.findById(recipeIngredient.getIngredientId())
                        .orElseThrow(() -> new NoSuchElementFoundException(NOT_FOUND_INGREDIENT));
                // then add to the RecipeIngredient (bridge table)
                recipe.addRecipeIngredient(new RecipeIngredient(recipe, ingredient));
            });
    recipeRepository.save(recipe);
}

Answer 1

Just clear the collection after loading the Recipe and then it should work fine. Hibernate will do the deletes for you automatically.