AgentSkillsCN

add-entity

创建具备多租户、审计、软删除及领域事件功能的领域实体。在向模块中添加新数据库实体时使用此功能。

SKILL.md
--- frontmatter
name: add-entity
description: Create a domain entity with multi-tenancy, auditing, soft-delete, and domain events. Use when adding new database entities to a module.
argument-hint: [ModuleName] [EntityName]

Add Entity

Create a domain entity following FSH patterns with full multi-tenancy support.

Entity Template

csharp
public sealed class {Entity} : AggregateRoot<Guid>, IHasTenant, IAuditableEntity, ISoftDeletable
{
    // Domain properties
    public string Name { get; private set; } = null!;
    public decimal Price { get; private set; }
    public string? Description { get; private set; }

    // IHasTenant - automatic tenant isolation
    public string TenantId { get; private set; } = null!;

    // IAuditableEntity - automatic audit trails
    public DateTimeOffset CreatedAt { get; set; }
    public string? CreatedBy { get; set; }
    public DateTimeOffset? LastModifiedAt { get; set; }
    public string? LastModifiedBy { get; set; }

    // ISoftDeletable - automatic soft deletes
    public DateTimeOffset? DeletedAt { get; set; }
    public string? DeletedBy { get; set; }

    // Private constructor for EF Core
    private {Entity}() { }

    // Factory method - the only way to create
    public static {Entity} Create(string name, decimal price, string tenantId)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(name);
        ArgumentOutOfRangeException.ThrowIfNegativeOrZero(price);

        var entity = new {Entity}
        {
            Id = Guid.NewGuid(),
            Name = name,
            Price = price,
            TenantId = tenantId
        };

        entity.AddDomainEvent(new {Entity}CreatedEvent(entity.Id));
        return entity;
    }

    // Domain methods for state changes
    public void UpdateDetails(string name, decimal price, string? description)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(name);
        ArgumentOutOfRangeException.ThrowIfNegativeOrZero(price);

        Name = name;
        Price = price;
        Description = description;

        AddDomainEvent(new {Entity}UpdatedEvent(Id));
    }
}

Domain Events

csharp
public sealed record {Entity}CreatedEvent(Guid {Entity}Id) : IDomainEvent;
public sealed record {Entity}UpdatedEvent(Guid {Entity}Id) : IDomainEvent;
public sealed record {Entity}DeletedEvent(Guid {Entity}Id) : IDomainEvent;

EF Core Configuration

csharp
public sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        builder.ToTable("{entities}");

        builder.HasKey(x => x.Id);

        builder.Property(x => x.Name)
            .IsRequired()
            .HasMaxLength(200);

        builder.Property(x => x.Price)
            .HasPrecision(18, 2);

        builder.Property(x => x.TenantId)
            .IsRequired()
            .HasMaxLength(64);

        builder.HasIndex(x => x.TenantId);

        // Global query filter for tenant isolation
        builder.HasQueryFilter(x => x.DeletedAt == null);
    }
}

Register in DbContext

csharp
public sealed class {Module}DbContext : DbContext
{
    public DbSet<{Entity}> {Entities} => Set<{Entity}>();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.HasDefaultSchema("{module}");
        modelBuilder.ApplyConfigurationsFromAssembly(typeof({Module}DbContext).Assembly);
    }
}

Add Migration

bash
dotnet ef migrations add Add{Entity} \
  --project src/Playground/Migrations.PostgreSQL \
  --startup-project src/Playground/Playground.Api

dotnet ef database update \
  --project src/Playground/Migrations.PostgreSQL \
  --startup-project src/Playground/Playground.Api

Interfaces Reference

InterfacePurposeAuto-Handled
IHasTenantTenant isolationQuery filtering
IAuditableEntityCreated/Modified trackingSaveChanges interceptor
ISoftDeletableSoft delete supportDelete interceptor
AggregateRoot<T>Domain events supportEvent dispatcher

Key Rules

  1. •Private constructor - EF Core needs it, but users use factory methods
  2. •Factory methods - All creation goes through Create() static method
  3. •Domain methods - State changes through methods, not property setters
  4. •Domain events - Raise events for significant state changes
  5. •Validation in methods - Validate in factory/domain methods, not entity
  6. •No public setters - Properties are private set

Checklist

  • • Implements AggregateRoot<Guid>
  • • Implements IHasTenant for tenant isolation
  • • Implements IAuditableEntity for audit trails
  • • Implements ISoftDeletable for soft deletes
  • • Has private constructor
  • • Has static factory method
  • • Domain events raised for state changes
  • • EF configuration created
  • • Added to DbContext
  • • Migration created