diff --git a/src/Objects/DataRow.php b/src/Objects/DataRow.php
index d658699..33aaaaf 100755
--- a/src/Objects/DataRow.php
+++ b/src/Objects/DataRow.php
@@ -51,11 +51,18 @@ public function getKeyDataItems() {
 
     public function prepare(array $keyFields, array $fieldMap, callable $dataItemManipulator)
     {
+        $this->validate();
         $this->setKeyFields($keyFields);
         $this->mapFields($fieldMap);
         $this->callDataItemManipulator($dataItemManipulator);
     }
 
+    private function validate() {
+        if (!$this->dataItems) {
+            throw new Exception('Data row contains no data items. The specified source may be producing an invalid data row.');
+        }
+    }
+
     private function setKeyFields(array $keyFields) {
         foreach($this->dataItems as $key => $dataItem) {
             if (in_array($dataItem->fieldName, $keyFields)) {