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Update README with loading types.

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Kevin Matsubara 2025-04-07 16:57:44 +02:00
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README.md
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@ -123,10 +123,32 @@ The following states are tracked in the `EntityState.State` property:
The `Find` functions require tracking, instead, use the `First` function, with a lambda for the ID. The `Find` functions require tracking, instead, use the `First` function, with a lambda for the ID.
### Loading types
Entity Framework Core has 3 common loading patterns.
* **Eager loading**: related data is loaded from the database as part of the initial query.
* **Explicit loading**: related data is explicitly loaded from the database later.
* **Lazy loading**: related data is loaded from the database accessing navigation property.
#### Eager loading
Uses the `include()` function to load related data in a query. The eager loading of a collection navigation may cause a performance issue, use `AsSplitQuery()` as needed to boost performance with large data sets. The `include()` function allows the `Where()` function to be used for filtering. If *tracking* is enabled, then the filter may return *incorrect* data, because it returns tracked records. Data may already be updated in the database, while the application is still using tracked data. Use the `ThenInclude()` function to get more dependencies.
### Explicit loading
Data can be explicitly loaded by executing a separate query that returns related entities. If *tracking* is enabled, the navigation properties of the newly loaded entity will refer to any entities already loaded.
### Lazy loading
This is the least recommended method of loading data. It requires the [Microsoft.EntityFrameworkCore.Proxies](https://www.nuget.org/packages/Microsoft.EntityFrameworkCore.Proxies/9.0.3) package. It must then be enabled in the DbContext configuration with `UseLazyLoadingProxies()`. Navigation properties must be virtual. It can cause extra database roundtrips, causing the [N+1 problem](https://docs.sentry.io/product/issues/issue-details/performance-issues/n-one-queries/).
## Database ## Database
### Relationships ### Relationships
* A **League** has one or more **Teams** (1:M) * A **League** has one or more **Teams** (1:M)
* A **Team** has one **Coach** (1:1) * A **Team** has one **Coach** (1:1)
* **Matches** are played by many **Teams** (M:M) * **Matches** are played by many **Teams** (M:M)
You can use [EF Core Power Tools](https://marketplace.visualstudio.com/items?itemName=ErikEJ.EFCorePowerTools) to create diagrams.