Added DeleteAll method to easily delete all entities in a table

Dapper.Contrib.Tests/Tests.cs

@@ -181,5 +181,18 @@ public void InsertFieldWithReservedName()
             }
 
         }
+
+        public void DeleteAll()
+        {
+            using (var connection = GetOpenConnection())
+            {
+                var id1 = connection.Insert(new User() { Name = "Alice", Age = 32 });
+                var id2 = connection.Insert(new User() { Name = "Bob", Age = 33 });
+                connection.DeleteAll<User>();
+                connection.Get<User>(id1).IsNull();
+                connection.Get<User>(id2).IsNull();
+            }
+        }
+
     }
 }

Dapper.Contrib/SqlMapperExtensions.cs

@@ -280,6 +280,23 @@ private static string GetTableName(Type type)
             return deleted > 0;
         }
 
+
+        /// <summary>
+        /// Delete all entities in the table related to the type T.
+        /// </summary>
+        /// <typeparam name="T">Type of entity</typeparam>
+        /// <param name="connection">Open SqlConnection</param>
+        /// <returns>true if deleted, false if none found</returns>
+        public static bool DeleteAll<T>(this IDbConnection connection, IDbTransaction transaction = null, int? commandTimeout = null) where T : class
+        {
+            var type = typeof(T);
+            var name = GetTableName(type);
+            var statement = String.Format("delete from {0}", name);
+            var deleted = connection.Execute(statement, null, transaction: transaction, commandTimeout: commandTimeout);
+            return deleted > 0;
+        }
+
+
 		public static ISqlAdapter GetFormatter(IDbConnection connection)
 		{
 			string name = connection.GetType().Name.ToLower();