An entity is a .NET POCO class that EF Core maps to a database table. Its properties represent stored columns, and each object represents a database row. A DbContext discovers entities exposed through DbSet<T> properties and builds an internal data model, including linked entities and their relationships. section 12.1.4 section 12.6
Working with an entity typically involves:
- Define a POCO class using EF Core conventions, such as an Id-suffixed property for a primary key. section 12.2.2
- Represent relationships with navigation collections and foreign-key properties; Recipe and Ingredient form a many-to-one relationship. section 12.1.4 section 12.2.2
- Create and track entity objects through DbContext, then call SaveChangesAsync to insert their rows. section 12.4.1
Recipe and Ingredient entities
A cooking API can define Recipe with RecipeId, Name, Method, and an ICollection<Ingredient>. Ingredient can define IngredientId, RecipeId, Name, Quantity, and Unit. Creating a Recipe together with its Ingredients lets EF Core generate the linked database rows and foreign-key values. section 12.2.2 section 12.4.1
Listing 12.2 Defining the EF Core entity classes
public class Recipe
{
public int RecipeId { get; set; }
public required string Name { get; set; }
public TimeSpan TimeToCook { get; set; }
public bool IsDeleted { get; set; }
public required string Method { get; set; }
public required ICollection<Ingredient> Ingredients { get; set; } #1
}
public class Ingredient
{
public int IngredientId { get; set; }
public int RecipeId { get; set; }
public required string Name { get; set; }
public decimal Quantity { get; set; }
public required string Unit { get; set; }
}
Inspect the compact Recipe and Ingredient class definitions, including keys, scalar properties, and the navigation collection. section 12.2.2
