Updating doctrine2 entities - doctrine-orm

Question

This must be really basic stuff since I did not find any discussion about it. However I have struggled with this for a while.
I have pretty basic many-to-many relation with extra field implemented like in this example (double one-to-many relation). This works nicely when creating new entities and saving them to database. I am now trying to create editing feature and came across some problems.
Lets say my main entity is called Recipe, which has many-to-many relation with Ingredient entity. Extra field(s) like "amount" are in RecipeIngredient entity. Recipe class has setRecipeIngredient method, which adds RecipeIngredient object to ingredients array.
Should I create some "clearRecipeIngredients" method to Recipe class, which would remove all RecipeIngredient objects? I would call this when editing Recipe, then creating new RecipeIngredient entities from my data and populating ingredients array like when creating new entity? I admit that my cascade settings are probably not set correctly this to work, but I try fixing it next.
Any related examples would be great.

Answer 1

Strictly speaking, as you mentioned, there is no many-to-many relationship here, but a one-to-many followed by a many-to-one.
About your question, I wouldn't perform a bulk "clear" each time I want to edit the recipe. Instead, I'd provide a fluent interface to mimic the steps that would be taken if you wanted to edit a paper-based recipe.
I provided a sample implementation below:
class Recipe
{
/**
* #OneToMany(targetEntity="RecipeIngredient", mappedBy="recipe")
*/
protected $recipeIngredients;
public function addIngredient(Ingredient $ingredient, $quantity)
{
// check if the ingredient already exists
// if it does, we'll just update the quantity
$recipeIngredient = $this->findRecipeIngredient($ingredient);
if ($recipeIngredient) {
$quantity += $recipeIngredient->getQuantity();
$recipeIngredient->updateQuantity($quantity);
}
else {
$recipeIngredient = new RecipeIngredient($this, $ingredient, $quantity);
$this->recipeIngredients[] = $recipeIngredient;
}
}
public function removeIngredient(Ingredient $ingredient)
{
$recipeIngredient = $this->findRecipeIngredient($ingredient);
if ($recipeIngredient) {
$this->recipeIngredients->removeElement($recipeIngredient);
}
}
public function updateIngredientQuantity(Ingredient $ingredient, $quantity)
{
$recipeIngredient = $this->findRecipeIngredient($ingredient);
if ($recipeIngredient) {
$recipeIngredient->updateQuantity($quantity);
}
}
protected function findRecipeIngredient(Ingredient $ingredient)
{
foreach ($this->recipeIngredients as $recipeIngredient) {
if ($recipeIngredient->getIngredient() === $ingredient) {
return $recipeIngredient;
}
}
return null;
}
}
Note: you'll need to setup cascade persist and orphan removal for this code to work properly.
Of course, if you take this approach, your UI shouldn't display a full form with all ingredients and quantities editable at once. Instead, all the ingredients should be listed, with a "delete" button on each line, as well as a "change quantity" button which would pop-up a (single-field) form to update the quantity, for example.