ef-core

name	ef-core
license	UNLICENSED
description	Use when working with Entity Framework Core in .NET applications, needing guidance on data context design, entity design, performance optimization, migrations, querying patterns, change tracking, security, or testing strategies.

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.