Although Knowledge-Based Database Design Systems have been proposed to assist the database designers, the characteristic of reusing the knowledge that may have acquired from previous experience like database design experts is not full addressed and satisfied, thus leading to the confusion of current conceptualisation work and providing no suggestion for overcoming the difficulties of object identification and semantic interpretation. To be truly helpful, two issues involved by experiences reuse have to be taken into account. Those are design by reuse and design for reuse. How to recall the useful experiences from the memory pool is the main concern of the former issue and the latter issue is concerned with how to structure knowledge including representation, segmentation and indexing. In this research, a unified theoretical framework based on the Dual-Base Knowledge Model is proposed to address these implications. In addition, the process model of the Dual-Base Knowledge Model is elaborated and then illustrated by a simulated example. By means of the two embedded mechanisms - the case retrieval and the knowledge accumulation mechanism in the process model, the relevant experiences can always be retrieved at the right time from the very large memory pool and the newly gained knowledge can be allocated in an appropriate place in the knowledge repository to be recalled in the next design session.