The data model of an application, the nature and format of data stored across executions, is typically a very rigid part of its early specication, even when prototyping, and changing it after code that relies on it was written can prove quite expensive and error-prone. Code and data in a running Lisp image can be dynamically modied. A MOP-based persistence library can bring this dynamicity to the data model. This enables to extend the easy prototyping way of development to the storage of data and helps avoiding interruptions of service. This article presents the conditions to do this portably and transparently.
Pierre Thierry, Simon E. B. Thierry