diff --git a/src/object-db.h b/src/object-db.h
new file mode 100644
index 0000000..8c31418
--- /dev/null
+++ b/src/object-db.h
@@ -0,0 +1,42 @@
+#ifndef OBJECT_DB_H
+#define OBJECT_DB_H
+
+#include <boost/exception/all.hpp>
+#include <vector>
+
+using namespace std;
+
+struct ObjectDBException : virtual boost::exception, virtual exception { };
+typedef boost::error_info<struct tag_errmsg, std::string> error_info_str;
+
+inline void throwException(const string &msg) { boost::throw_exception(ObjectDBException() << error_info_str(msg)); }
+
+typedef unsigned char Byte;
+typedef vector<Byte> Bytes;
+
+// OK. This name is a bit miss-leading, but this ObjectDB is really some storage
+// that stores the Ccnx ContentObjects of a file. So unlike a normal database,
+// this DB is per file.
+
+// The assumption is, the ContentObjects will be write to ObjectDB sequentially
+// This guarantees that when read, the Nth ContentObject read has the sequence number N as the last component of its name
+class ObjectDB
+{
+public:
+  virtual ~ObjectDB(){}
+
+  // assume sequential
+  virtual void
+  append(const Bytes &co) = 0;
+
+  // get next CO
+  virtual Bytes
+  next() = 0;
+
+  // size in terms of number of COs
+  virtual int
+  size() = 0;
+
+};
+
+#endif