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What is aggregate design pattern?
Aggregate is a pattern in Domain-Driven Design. A DDD aggregate is a cluster of domain objects that can be treated as a single unit. An example may be an order and its line-items, these will be separate objects, but it’s useful to treat the order (together with its line items) as a single aggregate.
What is aggregate modeling?
An aggregated model can be created from a combination of flat and/or aggregated models. Model aggregation generates an aggregation graph that describes the relations among the various modules. Changing the connections between modules in an aggregated model results in a different aggregation graph structure.
What is an aggregate software?
Aggregate Software means the Software, as a whole, to be developed or otherwise provided under the Statement of Work. For avoidance of doubt, if the Statement of Work provides for a single Software Deliverable, such Software Deliverable also constitutes Aggregate Software.
How are aggregates used in the domain model?
Also, Aggregates help us simplify the domain model by gathering multiple domain objects under a single abstraction around domain invariants that act as consistency and concurrency boundaries. This concept includes several implications. First of all, it is a conceptual whole meaning that it represents a cohesive notion of the domain model.
How to design and persist aggregates in white label?
Quite often, we need to map a Domain entity to a DTO / View Model to return to the user. In this case of Vinyl in White Label, we might need to return something like looks like this to the user: There’s the actual ArtistName, the artwork, the year it was released and more.
When do we make changes to our aggregates?
When we make changes to our aggregates ( UPDATE, DELETE, CREATE ), we’re performing COMMAND s. In this scenario, we need to have a complete aggregate pulled into memory in order to enforce any invariant rules before approving the COMMAND or rejecting it because some business rule isn’t being satisfied.
How to design and persist aggregates W / typescript?
As we define rules and constraints about how our isolated Domain Layer entities are allowed to relate to each other (1-to-1, 1-to-many, many-to-many), and which operations are valid at which times, several questions are introduced: How do we (cascade and) save this cluster of entities to the database?