Ontology有別於傳統的Relational Database擁有不同的架構以及儲存資料的方式。傳統的Relational Database力求節省使用空間，不將table彼此之間的關係考慮進去，以至於在schema change上是十分不易。Ontology整體架構是以class為主，此架構可由property來表現出classes之間的關係。相對地要建立Ontology必須考慮的點比傳統的Relational Database還要多，因此我們根據美國史丹佛大學所提出建立Ontology的七步驟，建立出一套完整的Taiwan Travel Ontology。 本文提出兩個case studies, case study 1討論新增一個attribute的schema change case study 2討論新增兩個subclasses的schema change。利用此兩個case studies來描述當發生schema change時Ontology與Relational Database之間的差異。如考慮save動作Ontology效能比Relational Database差，因為Relational Database發展成熟，save動作已優化。如不考慮save動作，Ontology確實比Relational Database效能高。Ontology可依據class的架構充分了解classes之間的關係，而Relational Database彼此tables之間是獨立的，並無法表達之間的關係。因此在日後維護上Ontology是優於Relational Database。
Different from traditional relational database, ontology uses a new way to store data as well as schema. Traditional relational database aims at saving space, thus stores no table relationship. On the other hand, ontology stores the relationship among its classes through property that should be considered in building it. We thus follow the seven steps by Stanford University to build a Taiwan Travel Ontology. This work presents two case studies of schema change. Case 1 discusses adding one attribute. Case 2 discusses extending two subclasses. Through the case studies, we probe into the difference between ontology and relational databases. If "save" time is included, database performs better because it is well optimized. If not, ontology do better. On the one hand, ontology stores relationship among its classes. On the other hand, relational database stores independent tables only, without their relationship. When it comes to schema change, ontology appears to be better than relational database.
