diff --git a/docker/docker-compose.yml b/docker/docker-compose.yml
index 137a6cc77..31b609b1e 100644
--- a/docker/docker-compose.yml
+++ b/docker/docker-compose.yml
@@ -12,6 +12,16 @@
     ports:
       - "5432:5432"
         
+  sqlserver:
+    image: mcr.microsoft.com/mssql/server:2022-latest
+    environment:
+      - ACCEPT_EULA=Y
+      - MSSQL_SA_PASSWORD=!Elsa2025@
+    ports:
+      - 1433:1433
+    volumes:
+      - sqlserver_data:/var/opt/mssql
+        
   mysql:
     image: mysql:8.0
     container_name: mysql
@@ -126,6 +136,7 @@
       - "14000:8080"
 
 volumes:
+  sqlserver_data:
   postgres-data:
   oracle-data-free1:
   mysql_data2:
diff --git a/src/apps/Elsa.Server.Web/appsettings.json b/src/apps/Elsa.Server.Web/appsettings.json
index 9010bf944..3fc86acdb 100644
--- a/src/apps/Elsa.Server.Web/appsettings.json
+++ b/src/apps/Elsa.Server.Web/appsettings.json
@@ -13,6 +13,7 @@
   "AllowedHosts": "*",
   "ConnectionStrings": {
     "Sqlite": "Data Source=App_Data/elsa.sqlite.db;Cache=Shared;",
+    "SqlServer": "Server=localhost,1433;Initial Catalog=Elsa;User=sa;Password=!Elsa2025@;Encrypt=false;PersistSecurityInfo=false",
     "MySql": "Server=localhost;Database=elsa;Uid=admin;Pwd=password;",
     "PostgreSql": "Server=localhost;Username=elsa;Database=elsa;Port=5432;Password=elsa;SSLMode=Prefer;MaxPoolSize=2000;Timeout=60",
     "Citus": "Server=localhost;Username=citus;Database=citus;Port=9700;Password=citus;SSLMode=Prefer;MaxPoolSize=2000;Timeout=60",
diff --git a/src/modules/Elsa.Workflows.Core/Contexts/ActivityExecutionContext.cs b/src/modules/Elsa.Workflows.Core/Contexts/ActivityExecutionContext.cs
index 6ecc474d1..ceae56077 100644
--- a/src/modules/Elsa.Workflows.Core/Contexts/ActivityExecutionContext.cs
+++ b/src/modules/Elsa.Workflows.Core/Contexts/ActivityExecutionContext.cs
@@ -124,7 +124,20 @@ public partial class ActivityExecutionContext : IExecutionContext, IDisposable
         {
             var containerVariables = (Activity as IVariableContainer)?.Variables ?? Enumerable.Empty<Variable>();
             var dynamicVariables = DynamicVariables;
-            return containerVariables.Concat(dynamicVariables).DistinctBy(x => x.Name);
+            var mergedVariables = new Dictionary<string, Variable>();
+            
+            foreach (var containerVariable in containerVariables)
+            {
+                var name = !string.IsNullOrEmpty(containerVariable.Name) ? containerVariable.Name : containerVariable.Id;
+                mergedVariables[name] = containerVariable;
+            }
+            
+            foreach (var dynamicVariable in dynamicVariables)
+            {
+                var name = !string.IsNullOrEmpty(dynamicVariable.Name) ? dynamicVariable.Name : dynamicVariable.Id;
+                mergedVariables[name] = dynamicVariable;
+            }
+            return mergedVariables.Values;
         }
     }
 
diff --git a/src/modules/Elsa.Workflows.Core/Memory/Variable.cs b/src/modules/Elsa.Workflows.Core/Memory/Variable.cs
index 78b577070..d3ed28f2f 100644
--- a/src/modules/Elsa.Workflows.Core/Memory/Variable.cs
+++ b/src/modules/Elsa.Workflows.Core/Memory/Variable.cs
@@ -21,7 +21,7 @@ public class Variable : MemoryBlockReference
     }
 
     /// <inheritdoc />
-    public Variable(string name, object? value = default) : this()
+    public Variable(string name, object? value = null) : this()
     {
         Name = name;
         Value = value;
@@ -30,7 +30,7 @@ public class Variable : MemoryBlockReference
     /// <summary>
     /// The name of the variable.
     /// </summary>
-    public string Name { get; set; } = default!;
+    public string Name { get; set; } = null!;
     
     /// <summary>
     /// A default value for the variable.
@@ -89,6 +89,12 @@ public class Variable<T> : Variable
         StorageDriverType = typeof(TDriver);
         return this;
     }
+
+    public Variable<T> WithId(string id)
+    {
+        Id = id;
+        return this;
+    }
 }
 
 /// <summary>