Resolved 2 issues with multi threaded code for issue #57

EntityFramework.Utilities/EntityFramework.Utilities/MappingHelper.cs

@@ -299,17 +299,36 @@ public static class EfMappingFactory
     {
         private static Dictionary<Type, EfMapping> cache = new Dictionary<Type, EfMapping>();
 
+        private static object lckObj = new object();
+
         public static EfMapping GetMappingsForContext(DbContext context)
         {
             var type = context.GetType();
+
             EfMapping mapping;
+
+            //Try our cache lookup.  If we find an item in the cache
+            //there is no reason to obtain a lock and limit this part 
+            //of the code to a single thread
             if (!cache.TryGetValue(type, out mapping))
             {
-                mapping = new EfMapping(context);
-                cache.Add(type, mapping);
+                //if the cache lookup fails lock so only a single thread
+                //at a time can access the add code
+                lock (lckObj)
+                {
+                    //Check the cache again.  If 2 threads failed the first cache lookup
+                    //the first thread will add the item to the cache
+                    //the second thread will wait on the lock and then pull the item from
+                    //cache.
+                    if (!cache.TryGetValue(type, out mapping))
+                    {
+                        mapping = new EfMapping(context);
+                        cache.Add(type, mapping);
+                    }
+                }
             }
+
             return mapping;
         }
-
     }
 }

EntityFramework.Utilities/EntityFramework.Utilities/SqlQueryProvider.cs

@@ -83,7 +83,7 @@ public void InsertItems<T>(IEnumerable<T> items, string schema, string tableName
 
         public void UpdateItems<T>(IEnumerable<T> items, string schema, string tableName, IList<ColumnMapping> properties, DbConnection storeConnection, int? batchSize, UpdateSpecification<T> updateSpecification)
         {
-            var tempTableName = "temp_" + tableName + "_" + DateTime.Now.Ticks;
+            var tempTableName = "temp_" + tableName + "_" + Guid.NewGuid().ToString("N");
             var columnsToUpdate = updateSpecification.Properties.Select(p => p.GetPropertyName()).ToDictionary(x => x);
             var filtered = properties.Where(p => columnsToUpdate.ContainsKey(p.NameOnObject) || p.IsPrimaryKey).ToList();
             var columns = filtered.Select(c => "[" + c.NameInDatabase + "] " + c.DataType);