ef-core

사용 방법

설치 명령을 복사하고 자신의 에이전트 환경에 설치하기 전에 소스 패키지를 확인하세요.
필요한 도구, 인증 정보, 지원 환경은 원본 문서에서 확인하세요.
입력과 원하는 산출물을 설명하고 출처와 결과를 대조하세요.

npx skills add https://github.com/codewithmukesh/dotnet-claude-kit --skill ef-core

시작 전 확인

설치에는 모델 구독, API 한도, 파일 접근 권한이 포함되지 않습니다.
별점 수와 설치 수는 활동 지표이며 독립적인 품질·보안 검증이 아닙니다.

원본 Skill 문서

원본 저장소의 제목, 예시, 코드, 표, 링크, 이미지를 유지해 표시합니다.

EF Core (.NET 10)

Core Principles

EF Core is the default ORM — Use it unless you have a specific reason not to (extreme perf, legacy DB without FK constraints). See ADR-003.
DbContext is a unit of work — Don't wrap it in another UoW abstraction. EF Core already implements Unit of Work and Repository patterns internally.
Queries should be projections — Use .Select() to project into DTOs instead of loading full entities. This avoids over-fetching and N+1 issues.
Migrations are code — Treat them like any other source code. Review them, test them, never auto-apply in production.

Patterns

DbContext Configuration

Use IEntityTypeConfiguration<T> to keep entity configs separate and discoverable.

csharp

// Persistence/AppDbContext.cs
public class AppDbContext(DbContextOptions<AppDbContext> options) : DbContext(options)
{
    public DbSet<Order> Orders => Set<Order>();
    public DbSet<Product> Products => Set<Product>();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.ApplyConfigurationsFromAssembly(typeof(AppDbContext).Assembly);
    }
}

// Persistence/Configurations/OrderConfiguration.cs
public class OrderConfiguration : IEntityTypeConfiguration<Order>
{
    public void Configure(EntityTypeBuilder<Order> builder)
    {
        builder.HasKey(o => o.Id);

        builder.Property(o => o.Total)
            .HasPrecision(18, 2);

        builder.HasMany(o => o.Items)
            .WithOne()
            .HasForeignKey(i => i.OrderId)
            .OnDelete(DeleteBehavior.Cascade);

        builder.HasIndex(o => o.CustomerId);
        builder.HasIndex(o => o.CreatedAt);
    }
}

Registration

csharp

// Program.cs
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseNpgsql(builder.Configuration.GetConnectionString("Default")));

Query Projections (Avoid Over-Fetching)

csharp

// GOOD — project to DTO, only loads needed columns
public async Task<OrderResponse?> GetOrderAsync(Guid id, CancellationToken ct)
{
    return await db.Orders
        .Where(o => o.Id == id)
        .Select(o => new OrderResponse(
            o.Id,
            o.Total,
            o.CreatedAt,
            o.Items.Select(i => new OrderItemResponse(i.ProductName, i.Quantity, i.Price)).ToList()))
        .FirstOrDefaultAsync(ct);
}

Pagination

csharp

public async Task<PagedList<OrderSummary>> ListOrdersAsync(int page, int pageSize, CancellationToken ct)
{
    var query = db.Orders
        .OrderByDescending(o => o.CreatedAt)
        .Select(o => new OrderSummary(o.Id, o.CustomerName, o.Total, o.Status));

    var totalCount = await query.CountAsync(ct);
    var items = await query
        .Skip((page - 1) * pageSize)
        .Take(pageSize)
        .ToListAsync(ct);

    return new PagedList<OrderSummary>(items, totalCount, page, pageSize);
}

ExecuteUpdateAsync / ExecuteDeleteAsync

Bulk operations that bypass change tracking for better performance.

csharp

// Update without loading entities
await db.Orders
    .Where(o => o.Status == OrderStatus.Pending && o.CreatedAt < cutoff)
    .ExecuteUpdateAsync(s => s
        .SetProperty(o => o.Status, OrderStatus.Expired)
        .SetProperty(o => o.UpdatedAt, clock.GetUtcNow()),
        ct);

// Delete without loading entities
await db.Orders
    .Where(o => o.Status == OrderStatus.Cancelled && o.CreatedAt < archiveCutoff)
    .ExecuteDeleteAsync(ct);

Interceptors

Use interceptors for cross-cutting concerns like audit trails and soft deletes.

csharp

public class AuditInterceptor(TimeProvider clock) : SaveChangesInterceptor
{
    public override ValueTask<InterceptionResult<int>> SavingChangesAsync(
        DbContextEventData eventData,
        InterceptionResult<int> result,
        CancellationToken ct = default)
    {
        var context = eventData.Context;
        if (context is null) return ValueTask.FromResult(result);

        var now = clock.GetUtcNow();

        foreach (var entry in context.ChangeTracker.Entries<IAuditable>())
        {
            switch (entry.State)
            {
                case EntityState.Added:
                    entry.Entity.CreatedAt = now;
                    entry.Entity.UpdatedAt = now;
                    break;
                case EntityState.Modified:
                    entry.Entity.UpdatedAt = now;
                    break;
            }
        }

        return ValueTask.FromResult(result);
    }
}

// Registration
builder.Services.AddDbContext<AppDbContext>((sp, options) =>
    options
        .UseNpgsql(connectionString)
        .AddInterceptors(sp.GetRequiredService<AuditInterceptor>()));

Compiled Queries

Use for hot-path queries that execute frequently with the same shape.

csharp

public class OrderQueries
{
    public static readonly Func<AppDbContext, Guid, CancellationToken, Task<Order?>> GetById =
        EF.CompileAsyncQuery((AppDbContext db, Guid id, CancellationToken ct) =>
            db.Orders
                .Include(o => o.Items)
                .FirstOrDefault(o => o.Id == id));
}

// Usage
var order = await OrderQueries.GetById(db, orderId, ct);

Value Converters

csharp

// Store enum as string
builder.Property(o => o.Status)
    .HasConversion<string>()
    .HasMaxLength(50);

// Strongly-typed IDs
public readonly record struct OrderId(Guid Value);

builder.Property(o => o.Id)
    .HasConversion(id => id.Value, value => new OrderId(value));

Migrations Workflow

bash

# Create a migration
dotnet ef migrations add AddOrderIndex --project src/MyApp.Infrastructure --startup-project src/MyApp.Api

# Review the generated migration — ALWAYS review before applying
# Check for data loss, index strategy, constraint names

# Apply to development database
dotnet ef database update --project src/MyApp.Infrastructure --startup-project src/MyApp.Api

# Generate SQL script for production
dotnet ef migrations script --idempotent --output migrations.sql

Global Query Filters

csharp

// Soft delete filter
builder.HasQueryFilter(o => !o.IsDeleted);

// Multi-tenant filter
builder.HasQueryFilter(o => o.TenantId == _tenantProvider.TenantId);

// Bypass when needed
var allOrders = await db.Orders.IgnoreQueryFilters().ToListAsync(ct);

Anti-patterns

Don't Wrap DbContext in a Repository

csharp

// BAD — unnecessary abstraction that limits EF Core's power
public interface IOrderRepository
{
    Task<Order?> GetByIdAsync(Guid id);
    Task AddAsync(Order order);
    Task SaveChangesAsync();
}

// GOOD — use DbContext directly in handlers
public class Handler(AppDbContext db)
{
    public async Task<Order?> Handle(GetOrder.Query query, CancellationToken ct)
    {
        return await db.Orders.FindAsync([query.Id], ct);
    }
}

Don't Use Lazy Loading

csharp

// BAD — lazy loading causes N+1 queries and hides data access
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseLazyLoadingProxies()); // DON'T

// GOOD — explicit loading with Include or projection
var orders = await db.Orders
    .Include(o => o.Items)
    .Where(o => o.CustomerId == customerId)
    .ToListAsync(ct);

Don't Use .ToListAsync() Then Filter in Memory

csharp

// BAD — loads ALL orders, filters in C#
var orders = await db.Orders.ToListAsync(ct);
var pending = orders.Where(o => o.Status == OrderStatus.Pending);

// GOOD — filter in the database
var pending = await db.Orders
    .Where(o => o.Status == OrderStatus.Pending)
    .ToListAsync(ct);

Don't Forget to Await Async Methods

csharp

// BAD — missing await, returns before save completes
public void Handle(CreateOrder.Command command)
{
    db.Orders.Add(order);
    db.SaveChangesAsync(); // Fire-and-forget BUG
}

// GOOD
public async Task Handle(CreateOrder.Command command, CancellationToken ct)
{
    db.Orders.Add(order);
    await db.SaveChangesAsync(ct);
}

Decision Guide

Scenario	Recommendation
Standard CRUD	DbContext with projections
Bulk updates (100+ rows)	`ExecuteUpdateAsync` / `ExecuteDeleteAsync`
Hot-path read query	Compiled query
Complex reporting query	Raw SQL with `FromSqlInterpolated` or Dapper
Audit trails	`SaveChangesInterceptor`
Multi-tenancy	Global query filter
Soft deletes	Global query filter + interceptor
Strongly-typed IDs	Value converter
Production migration	Idempotent SQL script, never auto-migrate

사용 방법

시작 전 확인

EF Core (.NET 10)

Core Principles

Patterns

DbContext Configuration

Registration

Query Projections (Avoid Over-Fetching)

Pagination

ExecuteUpdateAsync / ExecuteDeleteAsync

Interceptors

Compiled Queries

Value Converters

Migrations Workflow

Global Query Filters

Anti-patterns

Don't Wrap DbContext in a Repository

Don't Use Lazy Loading

Don't Use .ToListAsync() Then Filter in Memory

Don't Forget to Await Async Methods

Decision Guide

관련 작업

더 많은 Skills

avalonia

console-cli

desktop-mvvm

native-aot

ef-core

사용 방법

시작 전 확인

EF Core (.NET 10)

Core Principles

Patterns

DbContext Configuration

Registration

Query Projections (Avoid Over-Fetching)

Pagination

ExecuteUpdateAsync / ExecuteDeleteAsync

Interceptors

Compiled Queries

Value Converters

Migrations Workflow

Global Query Filters

Anti-patterns

Don't Wrap DbContext in a Repository

Don't Use Lazy Loading

Don't Use .ToListAsync() Then Filter in Memory

Don't Forget to Await Async Methods

Decision Guide

관련 작업

database-design

sql-pro

ef-core

db-migration-helper

더 많은 Skills

avalonia

console-cli

desktop-mvvm

native-aot