diff --git a/DigitalData.Core.Abstractions/Application/ICRUDService.cs b/DigitalData.Core.Abstractions/Application/ICRUDService.cs
index 9dfec8d..2c6074d 100644
--- a/DigitalData.Core.Abstractions/Application/ICRUDService.cs
+++ b/DigitalData.Core.Abstractions/Application/ICRUDService.cs
@@ -4,7 +4,7 @@ using DigitalData.Core.DTO;
 namespace DigitalData.Core.Abstractions.Application
 {
     public interface ICRUDService<TCreateDto, TReadDto, TUpdateDto, TEntity, TId>
-        where TCreateDto : class where TReadDto : class where TUpdateDto : IUnique<TId> where TEntity : class
+        where TCreateDto : class where TReadDto : class where TUpdateDto : IUnique<TId> where TEntity : class, IUnique<TId>
     {
         Task<DataResult<TId>> CreateAsync(TCreateDto createDto);
 
diff --git a/DigitalData.Core.Abstractions/Infrastructure/ICRUDRepository.cs b/DigitalData.Core.Abstractions/Infrastructure/ICRUDRepository.cs
index 4223d82..15e022f 100644
--- a/DigitalData.Core.Abstractions/Infrastructure/ICRUDRepository.cs
+++ b/DigitalData.Core.Abstractions/Infrastructure/ICRUDRepository.cs
@@ -5,7 +5,7 @@
     /// </summary>
     /// <typeparam name="TEntity">The type of the entity this repository works with.</typeparam>
     /// <typeparam name="TId">The type of the identifier for the entity.</typeparam>
-    public interface ICRUDRepository<TEntity, TId> where TEntity : class
+    public interface ICRUDRepository<TEntity, TId> where TEntity : class, IUnique<TId>
     {
         /// <summary>
         /// Adds a new entity to the repository.
diff --git a/DigitalData.Core.Application/CRUDService.cs b/DigitalData.Core.Application/CRUDService.cs
index 21cca2e..d737680 100644
--- a/DigitalData.Core.Application/CRUDService.cs
+++ b/DigitalData.Core.Application/CRUDService.cs
@@ -18,7 +18,7 @@ namespace DigitalData.Core.Application
     /// <typeparam name="TEntity">The entity type.</typeparam>
     /// <typeparam name="TId">The type of the identifier for the entity.</typeparam>
     public class CRUDService<TCRUDRepository, TCreateDto, TReadDto, TUpdateDto, TEntity, TId> : ICRUDService<TCreateDto, TReadDto, TUpdateDto, TEntity, TId>
-        where TCRUDRepository : ICRUDRepository<TEntity, TId> where TCreateDto : class where TReadDto : class where TUpdateDto : IUnique<TId> where TEntity : class
+        where TCRUDRepository : ICRUDRepository<TEntity, TId> where TCreateDto : class where TReadDto : class where TUpdateDto : IUnique<TId> where TEntity : class, IUnique<TId>
     {
         protected readonly TCRUDRepository _repository;
         protected readonly IMapper _mapper;
diff --git a/DigitalData.Core.Infrastructure/CRUDRepository.cs b/DigitalData.Core.Infrastructure/CRUDRepository.cs
index 1ac6b45..db8b902 100644
--- a/DigitalData.Core.Infrastructure/CRUDRepository.cs
+++ b/DigitalData.Core.Infrastructure/CRUDRepository.cs
@@ -1,4 +1,5 @@
-using DigitalData.Core.Abstractions.Infrastructure;
+using DigitalData.Core.Abstractions;
+using DigitalData.Core.Abstractions.Infrastructure;
 using Microsoft.EntityFrameworkCore;
 
 namespace DigitalData.Core.Infrastructure
@@ -14,7 +15,7 @@ namespace DigitalData.Core.Infrastructure
     /// It leverages the EF Core's DbContext and DbSet to perform these operations.
     /// </remarks>
     public class CRUDRepository<TEntity, TId, TDbContext> : ICRUDRepository<TEntity, TId>
-        where TEntity : class
+        where TEntity : class, IUnique<TId>
         where TDbContext : DbContext
     {
         protected readonly TDbContext _dbContext;