Reputation: 12528
Just wondering if someone can suggest how the domain class schema should be. I have a domain class called Category, but there can be sub-categories with the same domain (Category). For example, an appliance Toaster can be under category Kitchen, sub-category SmallAppliance.
class Category {
static hasMany = [appliances: Appliance, categories: Category]
String name
}
class Appliance {
static belongsTo = Category
static hasMany = [categories: Category]
}
Upvotes: 2
Views: 324
Reputation: 50285
A small tweak needed to the Appliance domain class. Guess it!! :)
We don't need the hasMany relationship in Appliance
for categories
. The relationship goes like this:
Category --> SubCategory (type of Category) --> Appliance
An appliance belongsTo
the parent category as well as to the subCategory
which in turn is a Category
itself. So belongsTo relationship is enough in appliance.
Use Instead:
class Appliance {
static belongsTo = Category
String name
}
class Category {
String name
static hasMany = [appliances: Appliance, subCategories: Category]
}
Here is a test case which can make understand things better:
//Category
def kitchen = new Category(name: "Kitchen")
kitchen.save()
//Appliance
def toaster = new Appliance(name: "Toaster")
kitchen.addToAppliances(toaster)
kitchen.save()
//Sub Categories
def electrical = new Category(name: "Electrical")
//Electrical category is a sub category of Kitchen
kitchen.addToSubCategories(electrical)
//Toaster is an appliance of Category Kitchen and Sub Category Electrical
electrical.addToAppliances(toaster)
kitchen.save()
assert kitchen
assert toaster
assert electrical
assert kitchen.appliances.size() == 1
kitchen.appliances.each{assert it.name == 'Toaster'}
assert kitchen.subCategories.size() == 1
kitchen.subCategories.each {assert it.name == 'Electrical'}
assert electrical.appliances.size() == 1
electrical.appliances.each {assert it.name == 'Toaster'}
Let know if it is still unclear.
Upvotes: 3