diff --git a/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/DbContextDatabaseApi.cs b/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/DbContextDatabaseApi.cs
index 7123b40ed6..f68df65aa9 100644
--- a/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/DbContextDatabaseApi.cs
+++ b/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/DbContextDatabaseApi.cs
@@ -13,20 +13,10 @@ namespace Volo.Abp.Uow.EntityFrameworkCore
         {
             DbContext = dbContext;
         }
-
-        public Task SaveChangesAsync()
-        {
-            return DbContext.SaveChangesAsync();
-        }
-
-        public Task SaveChangesAsync(CancellationToken cancellationToken)
+        
+        public Task SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
             return DbContext.SaveChangesAsync(cancellationToken);
         }
-
-        public Task CommitAsync()
-        {
-            return DbContext.SaveChangesAsync();
-        }
     }
 }
\ No newline at end of file
diff --git a/src/Volo.Abp/Volo/Abp/Uow/ChildUnitOfWork.cs b/src/Volo.Abp/Volo/Abp/Uow/ChildUnitOfWork.cs
index 6ad8706710..287bf39d42 100644
--- a/src/Volo.Abp/Volo/Abp/Uow/ChildUnitOfWork.cs
+++ b/src/Volo.Abp/Volo/Abp/Uow/ChildUnitOfWork.cs
@@ -18,17 +18,12 @@ namespace Volo.Abp.Uow
             _parent = parent;
         }
 
-        public Task SaveChangesAsync()
-        {
-            return _parent.SaveChangesAsync();
-        }
-
-        public Task SaveChangesAsync(CancellationToken cancellationToken)
+        public Task SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
             return _parent.SaveChangesAsync(cancellationToken);
         }
 
-        public Task CompleteAsync()
+        public Task CompleteAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
             return Task.CompletedTask;
         }
diff --git a/src/Volo.Abp/Volo/Abp/Uow/IDatabaseApi.cs b/src/Volo.Abp/Volo/Abp/Uow/IDatabaseApi.cs
index 1b65185832..a30e9eb8e8 100644
--- a/src/Volo.Abp/Volo/Abp/Uow/IDatabaseApi.cs
+++ b/src/Volo.Abp/Volo/Abp/Uow/IDatabaseApi.cs
@@ -5,10 +5,6 @@ namespace Volo.Abp.Uow
 {
     public interface IDatabaseApi
     {
-        Task SaveChangesAsync();
-
-        Task SaveChangesAsync(CancellationToken cancellationToken);
-
-        Task CommitAsync(); //TODO: Add CancellationToken to CommitAsync?
+        Task SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken));
     }
 }
\ No newline at end of file
diff --git a/src/Volo.Abp/Volo/Abp/Uow/IUnitOfWork.cs b/src/Volo.Abp/Volo/Abp/Uow/IUnitOfWork.cs
index a919dc6b32..495ee631e8 100644
--- a/src/Volo.Abp/Volo/Abp/Uow/IUnitOfWork.cs
+++ b/src/Volo.Abp/Volo/Abp/Uow/IUnitOfWork.cs
@@ -19,10 +19,8 @@ namespace Volo.Abp.Uow
 
         IDatabaseApi AddDatabaseApi(string id, IDatabaseApi databaseApi);
 
-        Task SaveChangesAsync();
+        Task SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken));
 
-        Task SaveChangesAsync(CancellationToken cancellationToken);
-
-        Task CompleteAsync();
+        Task CompleteAsync(CancellationToken cancellationToken = default(CancellationToken));
     }
 }
diff --git a/src/Volo.Abp/Volo/Abp/Uow/UnitOfWork.cs b/src/Volo.Abp/Volo/Abp/Uow/UnitOfWork.cs
index a9169eab12..3ff0f00ffc 100644
--- a/src/Volo.Abp/Volo/Abp/Uow/UnitOfWork.cs
+++ b/src/Volo.Abp/Volo/Abp/Uow/UnitOfWork.cs
@@ -24,15 +24,7 @@ namespace Volo.Abp.Uow
             //TODO: Remove itself from IUnitOfWorkManager
         }
 
-        public async Task SaveChangesAsync()
-        {
-            foreach (var databaseApi in _databaseApis.Values)
-            {
-                await databaseApi.SaveChangesAsync();
-            }
-        }
-
-        public async Task SaveChangesAsync(CancellationToken cancellationToken)
+        public async Task SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
             foreach (var databaseApi in _databaseApis.Values)
             {
@@ -40,11 +32,13 @@ namespace Volo.Abp.Uow
             }
         }
 
-        public async Task CompleteAsync()
+        public async Task CompleteAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
+            //TODO: We need a transaction management system.
+
             foreach (var databaseApi in _databaseApis.Values)
             {
-                await databaseApi.CommitAsync();
+                await databaseApi.SaveChangesAsync(cancellationToken);
             }
         }