Use base model for primary key.

Cicm.Database/Models/BaseModel.cs

@@ -0,0 +1,7 @@
+namespace Cicm.Database.Models
+{
+    public class BaseModel<TKey>
+    {
+        public TKey Id { get; set; }
+    }
+}

Cicm.Database/Models/BrowserTest.cs

@@ -32,9 +32,8 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class BrowserTest
+    public class BrowserTest : BaseModel<int>
     {
-        public int Id { get; set; }
         [DisplayName("User agent")]
         public string UserAgent { get; set; }
         public string Browser { get;   set; }

Cicm.Database/Models/Company.cs

@@ -37,7 +37,7 @@ using System.Linq;
 
 namespace Cicm.Database.Models
 {
-    public class Company
+    public class Company : BaseModel<int>
     {
         public Company()
         {
@@ -50,7 +50,6 @@ namespace Cicm.Database.Models
             SoundSynths             = new HashSet<SoundSynth>();
         }
 
-        public int    Id   { get; set; }
         public string Name { get; set; }
         [DisplayFormat(DataFormatString = "{0:d}")]
         public DateTime? Founded { get;        set; }

Cicm.Database/Models/CompanyDescription.cs

@@ -33,9 +33,8 @@ using System.ComponentModel.DataAnnotations;
 
 namespace Cicm.Database.Models
 {
-    public class CompanyDescription
+    public class CompanyDescription : BaseModel<int>
     {
-        public int Id        { get; set; }
         public int CompanyId { get; set; }
         [MaxLength(262144, ErrorMessage = "Description is too long")]
         public string Text { get; set; }

Cicm.Database/Models/CompanyLogo.cs

@@ -32,9 +32,8 @@ using System;
 
 namespace Cicm.Database.Models
 {
-    public class CompanyLogo
+    public class CompanyLogo : BaseModel<int>
     {
-        public int  Id        { get; set; }
         public int  CompanyId { get; set; }
         public int? Year      { get; set; }
         public Guid Guid      { get; set; }

Cicm.Database/Models/Forbidden.cs

@@ -30,9 +30,8 @@
 
 namespace Cicm.Database.Models
 {
-    public class Forbidden
+    public class Forbidden : BaseModel<int>
     {
-        public int    Id      { get; set; }
         public string Browser { get; set; }
         public string Date    { get; set; }
         public string Ip      { get; set; }

Cicm.Database/Models/Gpu.cs

@@ -36,7 +36,7 @@ using System.ComponentModel.DataAnnotations.Schema;
 
 namespace Cicm.Database.Models
 {
-    public class Gpu
+    public class Gpu : BaseModel<int>
     {
         public Gpu()
         {
@@ -44,7 +44,6 @@ namespace Cicm.Database.Models
             ResolutionsByGpu = new HashSet<ResolutionsByGpu>();
         }
 
-        public int    Id        { get; set; }
         public string Name      { get; set; }
         public int?   CompanyId { get; set; }
         [DisplayName("Model code")]

Cicm.Database/Models/GpusByMachine.cs

@@ -32,11 +32,10 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class GpusByMachine
+    public class GpusByMachine : BaseModel<long>
     {
-        public int  GpuId     { get; set; }
+        public int GpuId     { get; set; }
-        public int  MachineId { get; set; }
+        public int MachineId { get; set; }
-        public long Id        { get; set; }
 
         [DisplayName("GPU")]
         public virtual Gpu Gpu { get;         set; }

Cicm.Database/Models/InstructionSet.cs

@@ -32,14 +32,13 @@ using System.Collections.Generic;
 
 namespace Cicm.Database.Models
 {
-    public class InstructionSet
+    public class InstructionSet : BaseModel<int>
     {
         public InstructionSet()
         {
             Processors = new HashSet<Processor>();
         }
 
-        public int    Id   { get; set; }
         public string Name { get; set; }
 
         public virtual ICollection<Processor> Processors { get; set; }

Cicm.Database/Models/InstructionSetExtension.cs

@@ -33,14 +33,13 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class InstructionSetExtension
+    public class InstructionSetExtension : BaseModel<int>
     {
         public InstructionSetExtension()
         {
             InstructionSetExtensionsByProcessor = new HashSet<InstructionSetExtensionsByProcessor>();
         }
 
-        public int    Id        { get; set; }
         [DisplayName("Name")]
         public string Extension { get; set; }
 

Cicm.Database/Models/InstructionSetExtensionsByProcessor.cs

@@ -30,9 +30,8 @@
 
 namespace Cicm.Database.Models
 {
-    public class InstructionSetExtensionsByProcessor
+    public class InstructionSetExtensionsByProcessor : BaseModel<int>
     {
-        public int Id          { get; set; }
         public int ProcessorId { get; set; }
         public int ExtensionId { get; set; }
 

Cicm.Database/Models/Log.cs

@@ -30,9 +30,8 @@
 
 namespace Cicm.Database.Models
 {
-    public class Log
+    public class Log : BaseModel<int>
     {
-        public int    Id      { get; set; }
         public string Browser { get; set; }
         public string Ip      { get; set; }
         public string Date    { get; set; }

Cicm.Database/Models/Machine.cs

@@ -35,7 +35,7 @@ using System.ComponentModel.DataAnnotations.Schema;
 
 namespace Cicm.Database.Models
 {
-    public class Machine
+    public class Machine : BaseModel<int>
     {
         public Machine()
         {
@@ -46,7 +46,6 @@ namespace Cicm.Database.Models
             Storage    = new HashSet<StorageByMachine>();
         }
 
-        public int         Id         { get; set; }
         public int         CompanyId  { get; set; }
         public string      Name       { get; set; }
         public MachineType Type       { get; set; }

Cicm.Database/Models/MachineFamily.cs

@@ -32,14 +32,13 @@ using System.Collections.Generic;
 
 namespace Cicm.Database.Models
 {
-    public class MachineFamily
+    public class MachineFamily : BaseModel<int>
     {
         public MachineFamily()
         {
             Machines = new HashSet<Machine>();
         }
 
-        public int    Id        { get; set; }
         public int    CompanyId { get; set; }
         public string Name      { get; set; }
 

Cicm.Database/Models/MemoryByMachine.cs

@@ -32,7 +32,7 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class MemoryByMachine
+    public class MemoryByMachine : BaseModel<long>
     {
         public int         MachineId { get; set; }
         public MemoryType  Type      { get; set; }
@@ -40,7 +40,6 @@ namespace Cicm.Database.Models
         public long?       Size      { get; set; }
         [DisplayName("Speed (Hz)")]
         public double? Speed { get; set; }
-        public long Id { get;       set; }
 
         public virtual Machine Machine { get; set; }
     }

Cicm.Database/Models/MoneyDonation.cs

@@ -30,9 +30,8 @@
 
 namespace Cicm.Database.Models
 {
-    public class MoneyDonation
+    public class MoneyDonation : BaseModel<int>
     {
-        public int     Id       { get; set; }
         public string  Donator  { get; set; }
         public decimal Quantity { get; set; }
     }

Cicm.Database/Models/News.cs

@@ -33,9 +33,8 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class News
+    public class News : BaseModel<int>
     {
-        public int      Id   { get; set; }
         public DateTime Date { get; set; }
         public NewsType Type { get; set; }
         [DisplayName("Affected ID")]

Cicm.Database/Models/OwnedComputer.cs

@@ -30,9 +30,8 @@
 
 namespace Cicm.Database.Models
 {
-    public class OwnedComputer
+    public class OwnedComputer : BaseModel<int>
     {
-        public int        Id      { get; set; }
         public int        DbId    { get; set; }
         public string     Date    { get; set; }
         public StatusType Status  { get; set; }

Cicm.Database/Models/OwnedConsole.cs

@@ -30,9 +30,8 @@
 
 namespace Cicm.Database.Models
 {
-    public class OwnedConsole
+    public class OwnedConsole : BaseModel<int>
     {
-        public int        Id      { get; set; }
         public int        DbId    { get; set; }
         public string     Date    { get; set; }
         public StatusType Status  { get; set; }

Cicm.Database/Models/Processor.cs

@@ -36,7 +36,7 @@ using System.ComponentModel.DataAnnotations.Schema;
 
 namespace Cicm.Database.Models
 {
-    public class Processor
+    public class Processor : BaseModel<int>
     {
         public Processor()
         {
@@ -44,7 +44,6 @@ namespace Cicm.Database.Models
             ProcessorsByMachine      = new HashSet<ProcessorsByMachine>();
         }
 
-        public int    Id        { get; set; }
         public string Name      { get; set; }
         public int?   CompanyId { get; set; }
         [DisplayName("Model code")]

Cicm.Database/Models/ProcessorsByMachine.cs

@@ -32,13 +32,12 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class ProcessorsByMachine
+    public class ProcessorsByMachine : BaseModel<long>
     {
         public int ProcessorId { get; set; }
         public int MachineId   { get; set; }
         [DisplayName("Speed (MHz)")]
         public float? Speed { get; set; }
-        public long Id { get;      set; }
 
         public virtual Machine   Machine   { get; set; }
         public virtual Processor Processor { get; set; }

Cicm.Database/Models/Resolution.cs

@@ -33,14 +33,13 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class Resolution
+    public class Resolution : BaseModel<int>
     {
         public Resolution()
         {
             ResolutionsByGpu = new HashSet<ResolutionsByGpu>();
         }
 
-        public int   Id      { get; set; }
         public int   Width   { get; set; }
         public int   Height  { get; set; }
         public long? Colors  { get; set; }

Cicm.Database/Models/ResolutionsByGpu.cs

@@ -32,11 +32,10 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class ResolutionsByGpu
+    public class ResolutionsByGpu : BaseModel<long>
     {
-        public int  GpuId        { get; set; }
+        public int GpuId        { get; set; }
-        public int  ResolutionId { get; set; }
+        public int ResolutionId { get; set; }
-        public long Id           { get; set; }
 
         [DisplayName("GPU")]
         public virtual Gpu Gpu { get;               set; }

Cicm.Database/Models/SoundByMachine.cs

@@ -32,13 +32,12 @@ using System.ComponentModel;
 
 namespace Cicm.Database.Models
 {
-    public class SoundByMachine
+    public class SoundByMachine : BaseModel<long>
     {
-        public int  SoundSynthId { get; set; }
+        public int SoundSynthId { get; set; }
-        public int  MachineId    { get; set; }
+        public int MachineId    { get; set; }
-        public long Id           { get; set; }
 
-        public virtual Machine    Machine    { get; set; }
+        public virtual Machine Machine { get; set; }
         [DisplayName("Sound synthetizer")]
         public virtual SoundSynth SoundSynth { get; set; }
     }

Cicm.Database/Models/SoundSynth.cs

@@ -35,14 +35,13 @@ using System.ComponentModel.DataAnnotations.Schema;
 
 namespace Cicm.Database.Models
 {
-    public class SoundSynth
+    public class SoundSynth : BaseModel<int>
     {
         public SoundSynth()
         {
             SoundByMachine = new HashSet<SoundByMachine>();
         }
 
-        public int    Id        { get; set; }
         public string Name      { get; set; }
         public int?   CompanyId { get; set; }
         [DisplayName("Model code")]

Cicm.Database/Models/StorageByMachine.cs

@@ -30,13 +30,12 @@
 
 namespace Cicm.Database.Models
 {
-    public class StorageByMachine
+    public class StorageByMachine : BaseModel<long>
     {
         public int              MachineId { get; set; }
         public StorageType      Type      { get; set; }
         public StorageInterface Interface { get; set; }
         public long?            Capacity  { get; set; }
-        public long             Id        { get; set; }
 
         public virtual Machine Machine { get; set; }
     }

cicm_web/cicm_web.csproj

@@ -2,7 +2,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
     <TargetFramework>netcoreapp2.2</TargetFramework>
-    <Version>3.0.99.486</Version>
+    <Version>3.0.99.492</Version>
     <Company>Canary Islands Computer Museum</Company>
     <Copyright>Copyright © 2003-2018 Natalia Portillo</Copyright>
     <Product>Canary Islands Computer Museum Website</Product>