ef-core

Name: ef-core
Author: github

Entity Framework Core best practices guide covering design, performance, security, and testing patterns. Covers eight core areas: DbContext design, entity modeling, performance optimization, migrations, querying strategies, change tracking, security, and testing approaches Emphasizes practical patterns like DbContextFactory, IEntityTypeConfiguration separation, AsNoTracking() for read-only queries, and compiled queries for frequently executed operations Includes migration best practices such as descriptive naming, SQL verification before production, and data seeding through migrations Addresses common pitfalls: N+1 query problems, SQL injection prevention, appropriate DbContext lifetimes, and concurrency control for multi-user scenarios Recommends testing strategies using in-memory providers for unit tests and SQLite for integration tests

INSTALLATION

npx skills add https://github.com/github/awesome-copilot --skill ef-core

Run in your project or agent environment. Adjust flags if your CLI version differs.

SKILL.md

Entity Framework Core Best Practices

Your goal is to help me follow best practices when working with Entity Framework Core.

Data Context Design

Keep DbContext classes focused and cohesive

Use constructor injection for configuration options

Override OnModelCreating for fluent API configuration

Separate entity configurations using IEntityTypeConfiguration

Consider using DbContextFactory pattern for console apps or tests

Entity Design

Use meaningful primary keys (consider natural vs surrogate keys)

Implement proper relationships (one-to-one, one-to-many, many-to-many)

Use data annotations or fluent API for constraints and validations

Implement appropriate navigational properties

Consider using owned entity types for value objects

Performance

Use AsNoTracking() for read-only queries

Implement pagination for large result sets with Skip() and Take()

Use Include() to eager load related entities when needed

Consider projection (Select) to retrieve only required fields

Use compiled queries for frequently executed queries

Avoid N+1 query problems by properly including related data

Migrations

Create small, focused migrations

Name migrations descriptively

Verify migration SQL scripts before applying to production

Consider using migration bundles for deployment

Add data seeding through migrations when appropriate

Querying

Use IQueryable judiciously and understand when queries execute

Prefer strongly-typed LINQ queries over raw SQL

Use appropriate query operators (Where, OrderBy, GroupBy)

Consider database functions for complex operations

Implement specifications pattern for reusable queries

Change Tracking & Saving

Use appropriate change tracking strategies

Batch your SaveChanges() calls

Implement concurrency control for multi-user scenarios

Consider using transactions for multiple operations

Use appropriate DbContext lifetimes (scoped for web apps)

Security

Avoid SQL injection by using parameterized queries

Implement appropriate data access permissions

Be careful with raw SQL queries

Consider data encryption for sensitive information

Use migrations to manage database user permissions

Testing

Use in-memory database provider for unit tests

Create separate testing contexts with SQLite for integration tests

Mock DbContext and DbSet for pure unit tests

Test migrations in isolated environments

Consider snapshot testing for model changes

When reviewing my EF Core code, identify issues and suggest improvements that follow these best practices.