diff --git a/src/tables/TableKeyNotDefinedException.cpp b/src/tables/TableKeyNotDefinedException.cpp
new file mode 100644
index 0000000..30bedd0
--- /dev/null
+++ b/src/tables/TableKeyNotDefinedException.cpp
@@ -0,0 +1,19 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2015. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "tables/TableKeyNotDefinedException.h"
+
+TableKeyNotDefinedException::TableKeyNotDefinedException(llvm::StringRef key)
+    : msg("Unknown Table Key: ") {
+  msg += key;
+}
+
+const char* TableKeyNotDefinedException::what() const NT_NOEXCEPT {
+  return msg.c_str();
+}
+
+TableKeyNotDefinedException::~TableKeyNotDefinedException() NT_NOEXCEPT {}