Trabajando el relacionamiento entre entidades

Les comparto unos pequeños apuntes. 😁

Para este caso la entidad Products (N) y Category (1) tiene una relación N:1, lo cual quiere decir lo siguiente: Una categoría puede estar relacionada con muchos productos.

Para realizar esta asociación en código tenemos que entender lo siguiente: La entidad que tiene la cardinalidad 1 cuanta con un conjunto datos, en este caso de la entidad “ProductEntity”.

public ICollection <ProductEntity> Products { get; set; }

(Nos encontramos en la entidad CategoryEntity).

La entidad con la cardinalidad N (muchos) tiene que hacer referencia al id de la tabla con la cual se relaciona e indicar el nombre de esa tabla, hay que recordar que al pasar un modelo entidad relación a relacional en una relación N:1 la llave foránea se coloca en la entidad con cardinalidad N.

public string CategoryId { get; set; }

public CategoryEntity Category { get; set; }

(Nos encontramos en la entidad ProductsEntity).

Espero que sea de ayuda.
Saludos 👋.

No estoy muy seguro seguro sí usé el razonamiento correcto al crear las relaciones, así quedó:

    public class InOutEntity
    {
        [Key]
        [StringLength(50)]
        public string InOutId { get; set; }
        [Required]
        public DateTime InOutDate { get; set; }
        [Required]
        public int Quantity { get; set; }
        [Required]
        public bool IsInput { get; set; }
        public string StorageId { get; set; }
        public StorageEntity Storage { get; set; }
    }

    public class WherehouseEntity
    {
        [Key]
        [StringLength(50)]
        public string WherehouseId { get; set; }
        [Required]
        [StringLength(100)]
        public string WherehouseName { get; set; }
        [Required]
        [StringLength(100)]
        public string WherehouseAddress { get; set; }
        public string StorageId { get; set; }
        public StorageEntity Storage { get; set; }
    }

    public class StorageEntity
    {
        [Key]
        [StringLength(50)]
        public string StorageId { get; set; }
        [Required]
        public DateTime LastUpdate { get; set; }
        [Required]
        public int PartialQuantity { get; set; }
        public string ProductId { get; set; }
        public ProductEntity Product { get; set; }
        public ICollection<WherehouseEntity> Wherehouses { get; set; }
        public ICollection<InOutEntity> InOuts { get; set; }
    }

Genial

Creo haber utilizado la lógica correcta. Espero que si alguien sabe del tema por favor me corrija.
CategoryEntity

public class CategoryEntity
    {
        [Key]
        [StringLength(50)]
        public string CategoryId { get; set; }

        [Required]
        [StringLength(100)]
        public string CategoryName { get; set; }
        public ICollection<ProductEntity> Products { get; set; }
    }

ProductEntity

public class ProductEntity
    {
        [Key]
        [StringLength(10)]
        public string ProductId { get; set; }
        [Required]
        [StringLength(100)]
        public string ProductName { get; set; }

        [StringLength(600)]
        public string ProductDescription { get; set; }

        public int TotalQuantity { get; set; }
        [Required]
        [StringLength(50)]
        public string CategoryId { get; set; }
        public CategoryEntity Category { get; set; }
        public ICollection<StorageEntity> Storages { get; set; }
    }

WarehouseEntity

public class WarehouseEntity
    {
        [Key]
        public string WarehouseId { get; set; }
        [Required]
        [StringLength(50)]
        public string WarehouseName { get; set; }
        [MinLength(10)]
        public string WarehouseAddress { get; set; }
        public ICollection<StorageEntity> Storages { get; set; }
    }

StorageEntity

public class StorageEntity
    {
        [Key]
        [StringLength(10)]
        public string StorageId { get; set; }
        [Required]
        public DateTime LastUpdate { get; set; }
        [Required]
        public int PartialQuantity { get; set; }
        [Required]
        public string ProductId { get; set; }
        public ProductEntity Product { get; set; }
        [Required]
        public string WarehouseId { get; set; }
        public WarehouseEntity Warehouse { get; set; }
        public ICollection<InOutsEntity> InOuts { get; set; }

    }

InOutsEntity

public class InOutsEntity
    {
        [Key]
        [StringLength(50)]
        public string InOutsId { get; set; }
        [Required]
        public DateTime InOutDate { get; set; }
        [Required]
        public int Quantity { get; set; }
        [Required]
        public bool IsInput { get; set; }
        [Required]
        public string StorageId { get; set; }
        public StorageEntity Storages { get; set; }
    }

  public class InputOutputEntity
    {
        public string InOutId { get; set; }
        public DateTime InOutDate { get; set; }
        public int Quantity { get; set; }
        public bool IsInput { get; set; }
        public string StorageId { get; set; }
        public StorageEntity Storage { get; set; }
    }```

public class StorageEntity
    {
        [Key]
        [StringLength(50)]
        public string StorageId { get; set; }
        [Required]
        public DateTime LastUpdate { get; set; }
        [Required]
        public int PartialQuantity { get; set; }
        public string ProductId { get; set; }//Identificador del producto.
        public ProductEntity Product { get; set; } //Objeto que contiene el producto.
        public string WherehouseId { get; set; }//Identificador de la bodega.
        public WherehouseEntity Wherehouse { get; set; } //Objeto que contiene la bodega.
        public ICollection<InputOutputEntity> InputOutputs { get; set; } //Lista con todos las entradas/salidas existentes.
    }

<code>public class WherehouseEntity
    {
        [Key]
        [StringLength(50)]
        public string WherehouseId { get; set; }
        [Required]
        [StringLength(100)]
        public string WherehouseName { get; set; }
        [Required]
        [StringLength(100)]
        public string WherehouseAddress { get; set; }
        public ICollection<StorageEntity> Storages { get; set; } //Lista con todos los almacenes existentes.
    }

public class InputOutputEntity
    {
        [Key]
        [StringLength(50)]
        public string InOutId { get; set; }
        [Required]
        public DateTime InOutDate { get; set; }
        [Required]
        public int Quantity { get; set; }
        [Required]
        public bool IsInput { get; set; }
        public string StorageId { get; set; }//Identificador del almacen.
        public StorageEntity Storage { get; set; }//Objeto con el almacen.
    }

Reto
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Reto:

    public class ProductEntity
    {
        [Key]
        public int ProductId { get; set; }

        [Required]
        [StringLength(50)]
        public string ProductCode { get; set; }

        [Required]
        [StringLength(100)]
        public string ProductName { get; set; }

        [StringLength(600)]
        public string ProductDescription { get; set; }

        [Required]
        public decimal ProductTotalQuantity { get; set; }
        
        [Required]
        public int CategoryId { get; set; }

        public CategoryEntity Category { get; set; }

        public ICollection<StorageEntity> Storages { get; set; }
    }

    public class StorageEntity
    {
        [Key]
        public int StorageId { get; set; }

        [Required]
        [StringLength(50)]
        public string StorageCode { get; set; }

        [Required]
        public DateTime StorageLastUpdate { get; set; }

        [Required]
        public decimal StoragePartialQuantity { get; set; }

        [Required]
        public int ProductId { get; set; }

        public ProductEntity Product { get; set; }

        [Required]
        public int WarehouseId { get; set; }

        public WarehouseEntity Warehouse { get; set; }

        public ICollection<InOutEntity> InOutEntities { get; set; }
    }

    public class WarehouseEntity
    {
        [Key]
        public int WarehouseId { get; set; }

        [Required]
        [StringLength(50)]
        public string WarehouseCode { get; set; }

        [Required]
        [StringLength(100)]
        public string WarehouseName { get; set; }

        [Required]
        [StringLength(100)]
        public string WarehouseAddress { get; set; }

        public ICollection<StorageEntity> Storages { get; set; }
    }

    public class InOutEntity
    {
        [Key]
        public int InOutId { get; set; }

        [Required]
        [StringLength(50)]
        public string InOutCode { get; set; }

        [Required]
        public DateTime InOutDate { get; set; }

        [Required]
        public decimal InOutQuantity { get; set; }

        [Required]
        public bool InOutIsInput { get; set; }

        [Required]
        public int StorageId { get; set; }

        public StorageEntity Storage { get; set; }
    }