diff --git a/QueryBuilder.Tests/UpdateTests.cs b/QueryBuilder.Tests/UpdateTests.cs
index ca553d08..7f96d013 100644
--- a/QueryBuilder.Tests/UpdateTests.cs
+++ b/QueryBuilder.Tests/UpdateTests.cs
@@ -118,5 +118,48 @@ public void UpdateWithIgnoreAndColumnProperties()
                 c[EngineCodes.Firebird]);
         }
 
+
+
+        private class OrderProductComposite
+        {
+            public OrderProductComposite(string orderid, string productid, int quantity)
+            {
+                OrderId = orderid;
+                ProductId = productid;
+                Quantity = quantity;
+                Foo = "baz";
+            }
+
+            [Key("OrdId")]
+            public string OrderId { get; set; }
+
+            [Key]
+            public string ProductId { get; set; }
+
+            public int Quantity { get; set; }
+
+            [Column("Faa")]
+            public string Foo { get; set; }
+        }
+
+        [Fact]
+        public void UpdateWithKeyAttribute()
+        {
+            var order = new OrderProductComposite("ORD01", "PROD02", 20);
+
+            var query = new Query("OrderProductComposite").AsUpdate(order);
+
+            var c = Compile(query);
+
+
+            Assert.Equal(
+                "UPDATE [OrderProductComposite] SET [OrdId] = 'ORD01', [ProductId] = 'PROD02', [Quantity] = 20, [Faa] = 'baz' WHERE [OrdId] = 'ORD01' AND [ProductId] = 'PROD02'",
+                c[EngineCodes.SqlServer]);
+
+            Assert.Equal(
+              "UPDATE \"ORDERPRODUCTCOMPOSITE\" SET \"ORDID\" = 'ORD01', \"PRODUCTID\" = 'PROD02', \"QUANTITY\" = 20, \"FAA\" = 'baz' WHERE \"ORDID\" = 'ORD01' AND \"PRODUCTID\" = 'PROD02'",
+              c[EngineCodes.Firebird]);
+        }
+
     }
 }
\ No newline at end of file
diff --git a/QueryBuilder/ColumnAttribute.cs b/QueryBuilder/ColumnAttribute.cs
index 88539923..3ef71b83 100644
--- a/QueryBuilder/ColumnAttribute.cs
+++ b/QueryBuilder/ColumnAttribute.cs
@@ -18,4 +18,18 @@ public ColumnAttribute(string name)
         }
 
     }
+
+
+    /// <summary>
+    /// This class is used as metadata on a property to determine if it is a primary key
+    /// </summary>
+    public class KeyAttribute : ColumnAttribute
+    {
+        public KeyAttribute([System.Runtime.CompilerServices.CallerMemberName] string name = "")
+        : base(name)
+        {
+
+        }
+
+    }
 }
diff --git a/QueryBuilder/Query.Insert.cs b/QueryBuilder/Query.Insert.cs
index f0696217..f08e8ab9 100644
--- a/QueryBuilder/Query.Insert.cs
+++ b/QueryBuilder/Query.Insert.cs
@@ -9,26 +9,34 @@ public partial class Query
     {
         public Query AsInsert(object data, bool returnId = false)
         {
-            var dictionary = new Dictionary<string, object>();
+            var dictionary = BuildDictionaryOnInsert(data);
+
+            return AsInsert(dictionary, returnId);
+        }
 
-            var props = data.GetType()
-                        .GetRuntimeProperties()
-                        .Where(_ => _.GetCustomAttribute(typeof(IgnoreAttribute)) == null);
 
-            foreach (var item in props)
+        private Dictionary<string, object> BuildDictionaryOnInsert(object data)
+        {
+
+            var dictionary = new Dictionary<string, object>();
+            var props = data.GetType().GetRuntimeProperties();
+
+            foreach (PropertyInfo property in props)
             {
-                var attr = item.GetCustomAttribute(typeof(ColumnAttribute)) as ColumnAttribute;
-                if (attr != null)
-                {
-                    dictionary.Add(attr.Name, item.GetValue(data));
-                }
-                else
+                if (property.GetCustomAttribute(typeof(IgnoreAttribute)) != null)
                 {
-                    dictionary.Add(item.Name, item.GetValue(data));
+                    continue;
                 }
+
+                var value = property.GetValue(data);
+
+                var colAttr = property.GetCustomAttribute(typeof(ColumnAttribute)) as ColumnAttribute;
+                var name = colAttr?.Name ?? property.Name;
+                  
+                dictionary.Add(name, value);
             }
 
-            return AsInsert(dictionary, returnId);
+            return dictionary;
         }
 
         public Query AsInsert(IEnumerable<string> columns, IEnumerable<object> values)
diff --git a/QueryBuilder/Query.Update.cs b/QueryBuilder/Query.Update.cs
index b1c87c52..95653f8a 100644
--- a/QueryBuilder/Query.Update.cs
+++ b/QueryBuilder/Query.Update.cs
@@ -5,30 +5,47 @@
 
 namespace SqlKata
 {
+
     public partial class Query
     {
 
         public Query AsUpdate(object data)
         {
-            var dictionary = new Dictionary<string, object>();
+            var dictionary = BuildDictionaryOnUpdate(data);
+            return AsUpdate(dictionary);
+        }
 
-            var props = data.GetType().GetRuntimeProperties()
-                .Where(_ => _.GetCustomAttribute(typeof(IgnoreAttribute)) == null);
 
-            foreach (var item in props)
+        private static Dictionary<Type, List<PropertyInfo>> CacheDictionaryProperties = new Dictionary<Type, List<PropertyInfo>>(); 
+
+
+        private Dictionary<string, object> BuildDictionaryOnUpdate(object data)
+        {
+
+            var dictionary = new Dictionary<string, object>();
+            var props = data.GetType().GetRuntimeProperties();
+
+            foreach (PropertyInfo property in props)
             {
-                var attr = item.GetCustomAttribute(typeof(ColumnAttribute)) as ColumnAttribute;
-                if (attr != null)
-                {
-                    dictionary.Add(attr.Name, item.GetValue(data));
+                if (property.GetCustomAttribute(typeof(IgnoreAttribute)) != null){
+                    continue;
                 }
-                else
+
+                var value = property.GetValue(data);
+
+                var colAttr = property.GetCustomAttribute(typeof(ColumnAttribute)) as ColumnAttribute;
+                var name = colAttr?.Name ?? property.Name;
+                if(colAttr != null)
                 {
-                    dictionary.Add(item.Name, item.GetValue(data));
-                }
+                    if((colAttr as KeyAttribute) != null)
+                    {
+                        this.Where(name, value);
+                    }
+                } 
+                dictionary.Add(name, value);
             }
 
-            return AsUpdate(dictionary);
+            return dictionary;
         }
 
         public Query AsUpdate(IEnumerable<string> columns, IEnumerable<object> values)