в общем, создала модели Магазин и МагазинСуши для бд

SushiBarDatabaseImplement/Implements/ShopStorage.cs

@@ -0,0 +1,13 @@
+using SushiBarContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SushiBarDatabaseImplement.Implements
+{
+    public class ShopStorage : IShopStorage
+    {
+    }
+}

SushiBarDatabaseImplement/Models/Shop.cs

@@ -0,0 +1,112 @@
+using SushiBarContracts.BindingModel;
+using SushiBarContracts.ViewModels;
+using SushiBarDataModels;
+using SushiBarDataModels.Models;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Xml.Linq;
+
+namespace SushiBarDatabaseImplement.Models
+{
+    public class Shop : IShopModel
+    {
+        public int Id { get; private set; }
+
+        [Required]
+        public string ShopName { get; private set; }
+
+        [Required]
+        public string Address { get; private set; }
+
+        [Required]
+        public DateTime DateOpening { get; private set; }
+
+        [Required]
+        public int MaxCountSushis { get; private set; }
+
+        [ForeignKey("ShopId")]
+        public List<ShopSushi> Sushis { get; private set; } = new();
+
+        private Dictionary<int, (ISushiModel, int)>? _shopSushis = null;
+
+        [NotMapped]
+        public Dictionary<int, (ISushiModel, int)> ShopSushis
+        {
+            get
+            {
+                if (_shopSushis == null)
+                {
+                    _shopSushis = Sushis.ToDictionary(recPC => recPC.SushiId, recPC => (recPC.Sushi as ISushiModel, recPC.Count));
+                }
+                return _shopSushis;
+            }
+        }
+
+        public static Shop Create(SushiBarDatabase context, ShopBindingModel model)
+        {
+            return new Shop()
+            {
+                Id = model.Id,
+                ShopName = model.ShopName,
+                Address = model.Address,
+                MaxCountSushis = model.MaxCountSushis,
+                Sushis = model.ShopSushis.Select(x => new ShopSushi
+                {
+                    Sushi = context.Sushis.First(y => y.Id == x.Key), Count = x.Value.Item2
+                }).ToList()
+            };
+        }
+        public void Update(ShopBindingModel model)
+        {
+            ShopName = model.ShopName;
+            Address = model.Address;
+            DateOpening = model.DateOpening;
+            MaxCountSushis = model.MaxCountSushis;
+        }
+        public ShopViewModel GetViewModel => new()
+        {
+            Id = Id,
+            ShopName = ShopName,
+            Address = Address,
+            DateOpening = DateOpening,
+            MaxCountSushis = MaxCountSushis,
+            ShopSushis = ShopSushis
+        };
+        public void UpdateComponents(SushiBarDatabase context, ShopBindingModel model)
+        {
+            var ShopSushis = context.ShopSushis.Where(rec => rec.ShopId == model.Id).ToList();
+            if (ShopSushis != null && ShopSushis.Count > 0)
+            {
+                // удалили те, которых нет в модели
+                context.ShopSushis.RemoveRange(ShopSushis.Where(rec => !model.ShopSushis.ContainsKey(rec.SushiId)));
+                context.SaveChanges();
+                ShopSushis = context.ShopSushis.Where(rec => rec.ShopId == model.Id).ToList();
+                // обновили количество у существующих записей
+                foreach (var updateSushi in ShopSushis)
+                {
+                    updateSushi.Count = model.ShopSushis[updateSushi.SushiId].Item2;
+                    model.ShopSushis.Remove(updateSushi.SushiId);
+                }
+                context.SaveChanges();
+            }
+            var shop = context.Shops.First(x => x.Id == Id);
+            foreach (var elem in model.ShopSushis)
+            {
+                context.ShopSushis.Add(new ShopSushi
+                {
+                    Shop = shop,
+                    Sushi = context.Sushis.First(x => x.Id == elem.Key),
+                    Count = elem.Value.Item2
+                });
+                context.SaveChanges();
+            }
+            _shopSushis = null;
+        }
+    }
+}

SushiBarDatabaseImplement/Models/ShopSushi.cs

@@ -0,0 +1,27 @@
+using SushiBarListImplements.Models;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Runtime.ConstrainedExecution;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SushiBarDatabaseImplement.Models
+{
+    public class ShopSushi
+    {
+        public int Id { get; set; }
+
+        [Required]
+        public int SushiId { get; set; }
+
+        [Required]
+        public int ShopId { get; set; }
+
+        [Required]
+        public int Count { get; set; }
+        public virtual Shop Shop { get; set; } = new();
+        public virtual Sushi Sushi { get; set; } = new();
+    }
+}

SushiBarDatabaseImplement/Models/Sushi.cs

@@ -10,11 +10,15 @@ namespace SushiBarDatabaseImplement.Models
     public class Sushi : ISushiModel
     {
         public int Id { get; set; }
+
         [Required]
         public string SushiName { get; set; } = string.Empty;
+
         [Required]
         public double Price { get; set; }
+
         private Dictionary<int, (IComponentModel, int)>? _sushiComponents = null;
+
         [NotMapped]
         public Dictionary<int, (IComponentModel, int)> SushiComponents
         {

SushiBarDatabaseImplement/SushiBarDatabase.cs

@@ -24,5 +24,7 @@ namespace SushiBarDatabaseImplement
         public virtual DbSet<Sushi> Sushis { set; get; }
         public virtual DbSet<SushiComponent> SushiComponents { set; get; }
         public virtual DbSet<Order> Orders { set; get; }
+        public virtual DbSet<Shop> Shops { set; get; }
+        public virtual DbSet<ShopSushi> ShopSushis { set; get; }
     }
 }