добавила реализауию сервиса (услуги)

BeautySalon/BeautySalonDBModels/Implements/ServiceDB.cs

@@ -0,0 +1,83 @@
+using BeautySalonDBModels.Models;
+using Npgsql;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BeautySalonDBModels.Implements
+{
+    public class ServiceDB : AbstractWorkWithStorage<Service>
+    {
+        public override void Add(Service service)
+        {
+            using var conn = GetConnection();
+            conn.Open();
+            using var cmd = new NpgsqlCommand("INSERT INTO services (service_name, price, specialisation_id) " +
+                "VALUES (@ServiceName, @Price, @SpecialisationId)", conn);
+            cmd.Parameters.AddWithValue("@ServiceName", service.ServiceName);
+            cmd.Parameters.AddWithValue("@Price", service.Price);
+            cmd.Parameters.AddWithValue("@SpecialisationId", service.SpecialisationId);
+            cmd.ExecuteNonQuery();
+        }
+
+        public override Service? GetObject(int id)
+        {
+            using var conn = GetConnection();
+            conn.Open();
+            using var cmd = new NpgsqlCommand("SELECT * FROM services WHERE service_id = {id}", conn);
+            using var reader = cmd.ExecuteReader();
+            if (reader.Read())
+            {
+                return new Service
+                {
+                    ServiceId = reader.GetInt32(0),
+                    ServiceName = reader.GetString(1),
+                    Price = reader.GetDouble(2),
+                    SpecialisationId = reader.GetInt32(3)
+                };
+            }
+            return null;
+        }
+
+        public override List<Service> GetObjects()
+        {
+            var services = new List<Service>();
+            using var conn = GetConnection();
+            conn.Open();
+            using var cmd = new NpgsqlCommand("SELECT * FROM services order by service_id", conn);
+            using var reader = cmd.ExecuteReader();
+            while (reader.Read())
+            {
+                services.Add(new Service
+                {
+                    ServiceId = reader.GetInt32(0),
+                    ServiceName = reader.GetString(1),
+                    Price = reader.GetDouble(2),
+                    SpecialisationId = reader.GetInt32(3)
+                });
+            }
+            return services;
+        }
+
+        public override Service? Remove(int id)
+        {
+            var service = GetObject(id);
+            using var conn = GetConnection();
+            conn.Open();
+            using var cmd = new NpgsqlCommand("delete from services where service_id = {id}", conn);
+            cmd.ExecuteNonQuery();
+            return service;
+        }
+
+        public override void Update(Service service)
+        {
+            using var conn = GetConnection();
+            conn.Open();
+            using var cmd = new NpgsqlCommand("update service set service_name = {service.ServiceName}, " +
+                "price = {service.Price}, specialisation_id = {service.SpecialisationId} where service_id = {service.ServiceId}", conn);
+            cmd.ExecuteNonQuery();
+        }
+    }
+}