Skip to main content

Loading aggregates with EF Core

In Domain-Driven Design (DDD), an aggregate is a cluster of domain objects that are treated as a single unit for the purpose of data changes. The aggregate has a root and a boundary:

  • Aggregate Root: This is a single, specific entity that acts as the primary point of interaction. It guarantees the consistency of changes being made within the aggregate by controlling access to its components. The aggregate root enforces all business rules and invariants within the aggregate boundary.

  • Boundary: The boundary defines what is inside the aggregate and what is not. It includes the aggregate root and other entities or value objects that are controlled by the root. Changes to entities or value objects within the boundary must go through the aggregate root to ensure consistency.

An example of an aggregate is an Order(which is the Aggregate root) together with OrderItems(entities inside the Aggregate).

The primary function of an aggregate is to ensure data consistency. All invariants are maintained within this boundary.Therefore it is important that when you fetch an aggregate in your application code, that the full aggregate is loaded into memory.

One way to achieve this in EF Core is by taking advantage of the AutoInclude functionality. This allows us to include related data every time an entity is loaded from the database.

If we apply this to the Order example above, the mapping logic would look like this:

if we now fetch the Orders, all OrderItems will be includes as well.

Remark:If we don’t want to load the related data it is still possible by using the IgnoreAutoIncludes method:

More information

Eager Loading of Related Data - EF Core | Microsoft Learn

    Popular posts from this blog

    DevToys–A swiss army knife for developers

    As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities.  DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Color B

    Help! I accidently enabled HSTS–on localhost

    I ran into an issue after accidently enabling HSTS for a website on localhost. This was not an issue for the original website that was running in IIS and had a certificate configured. But when I tried to run an Angular app a little bit later on http://localhost:4200 the browser redirected me immediately to https://localhost . Whoops! That was not what I wanted in this case. To fix it, you need to go the network settings of your browser, there are available at: chrome://net-internals/#hsts edge://net-internals/#hsts brave://net-internals/#hsts Enter ‘localhost’ in the domain textbox under the Delete domain security policies section and hit Delete . That should do the trick…

    Azure DevOps/ GitHub emoji

    I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.