Complex Type properties

Breeze supports the concept that any data property of an Entity can be an instance of a complex type. A complexType property is a data property that represents a defined collection of other data Properties and possibly nested complex type properties. An example might be a location property on a Customer class, where the location consists of an address, city, state, and zip code. In this case, the location property on the Customer type is termed a complex property, and the data type of this property would be a complex type of type location. The path to a city in this case would be

  aCustomer.Location.City.

Complex types in Breeze are much like entity type’s but with some key differences.

• Complex types do not have identities (key properties in breeze) and therefore cannot exist independently. Complex types can only exist as properties on entity types or other complex types.
  • This is actually slightly incorrect, you can create an ‘unbound’ instance of a complexType with the complexType.createInstance method but when you assign it, you are simply copying its values onto an existing instance.
• Complex types cannot contain navigation properties or foreign key data properties.
• Complex type properties, aCustomer.Location in the example above, are not nullable and are automatically created when their parent entity or complex object is created. Note that any of the properties of the complex type instance itself ( that are not themselves complex types) may be nullable.
• When instances of a complex type are assigned, the contents of the complexType instance are copied to the target. Complex types are not assigned by reference.

Every instance of a complex type object has a ComplexAspect property automatically added by Breeze:

• The ComplexAspect property – This contains information about the ‘parentage’ of this instance and any original values for change tracking purposes. The ComplexAspect is analogous to the EntityAspect property on every Breeze entity.

Interactions involving Complex types

Query/Save

Queries can return ComplexTypes and ComplexType properties can be queried, i.e.

 EntityQuery.From<Customer>().Where(c => c.Location.City.StartsWith("A");

Entities containing complex types may be saved.

Property paths

IEntity.PropertyChanged and EntityManager.EntityChanged events return “property paths” whenever a property of an embedded complex type is modified. i.e. Location.City.

MetadataStore methods

Analagous to the EntityTypes property and the GetEntityType method, the MetadataStore also has a ComplexTypes property and a GetComplexType method.

Both EntityType and ComplexType classes extend the StructuralType abstract class. The StructuralType class implements an IsEntityType property that will return ‘true’ for EntityTypes and ‘false’ for ComplexTypes.

Validation

Validating an entity validates all of the properties, including complex type properties of an entity

Validating a complex type property involves validating all of its properties. Property level validation errors involving complex type properties include the “property path” to the errant property.