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EF Core Labs

Hands-on EF Core query, update, transaction, concurrency, and production-debugging exercises.

15 drillsPractice one at a timeOrdered pathCoding problem

Recommended start

Order DTO Projection

Builds a read-only EF Core projection with aggregates, stable ordering, and bounded results instead of loading an entity graph.

Easy~15 minStep 1 of 15

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1Order DTO ProjectionRecommended startBuilds a read-only EF Core projection with aggregates, stable ordering, and bounded results instead of loading an entity graph.Coding problemEasy~15 min.NETASP.NET CoreC#Practice 2

Practice order

15 drillsOne at a time

1Order DTO ProjectionUp next / Easy / ~15 min
2Refactor N Plus OneMedium / ~25 min
3Composable FiltersEasy / ~15 min
4

Refactor N Plus OneReplaces a parent query plus one status query per row with one server-side projection.Coding problemMedium~25 min.NETASP.NET CoreC#

Practice

3Composable FiltersBuilds optional EF Core predicates while preserving server translation, stable ordering, and a bounded result.Coding problemEasy~15 min.NETASP.NET CoreC#Practice

4EF Keyset PageImplements descending keyset pagination in LINQ using a compound timestamp-and-id cursor.Coding problemMedium~25 min.NETASP.NET CoreC#Practice

5Tracked Split QueryUses `AsSplitQuery` deliberately for a tracked aggregate with multiple collections and explains its consistency boundary.Coding problemMedium~25 min.NETASP.NET CoreC#Practice

6Bulk Session ExpiryPerforms a set-based bulk update without loading session entities into the change tracker.Coding problemEasy~15 min.NETASP.NET CoreC#Practice

7Rowversion ConflictUses the client's original rowversion to detect a lost update and return a deliberate conflict response.Coding problemMedium~25 min.NETASP.NET CoreC#Practice

8Unique Email ConflictRelies on a database unique constraint and translates only the expected provider error into a domain conflict.Coding problemMedium~25 min.NETASP.NET CoreC#Practice

9Targeted Property UpdateAttaches a key-only stub and marks one property modified for a narrow update while naming the rules this pattern bypasses.Coding problemMedium~25 min.NETASP.NET CoreC#Practice

10Order Plus OutboxPersists domain state and its outbox message in one SaveChanges transaction without publishing inside the request transaction.Coding problemMedium~25 min.NETASP.NET CoreC#Practice

11Retry Transaction UnitWraps a complete explicit transaction in the provider execution strategy and creates fresh context state for each retry attempt.Coding problemHard~35 min.NETASP.NET CoreC#Practice

12EF Query CancellationCarries the ASP.NET Core request token into a bounded EF Core query while keeping cancellation separate from business rollback guarantees.Coding problemEasy~15 min.NETASP.NET CoreC#Practice

13Bounded EF ImportProcesses a large import in chunks with fresh DbContexts, idempotent keys, cancellation, and bounded tracker growth.Coding problemHard~35 min.NETASP.NET CoreC#Practice

14Tag Slow QueryAdds a stable query tag and inspects generated SQL without embedding user data or enabling unsafe global logging.Coding problemMedium~25 min.NETASP.NET CoreC#Practice

15Pooled Tenant ContextWraps a pooled DbContext factory so every request assigns tenant state before a global query filter can run.Coding problemHard~35 min.NETASP.NET CoreC#Practice

EF Keyset Page

Medium / ~25 min

5Tracked Split QueryMedium / ~25 min

6Bulk Session ExpiryEasy / ~15 min

7Rowversion ConflictMedium / ~25 min

8Unique Email ConflictMedium / ~25 min

+7 more drills in this section

EF Core Labs - .NET Backend | Aporeon