The schema in a relational database refers to the tables, fields and also the existing relationship between the fields and tables. Schemas are stored in a data dictionary, it is considered as the graphic model of a database.Schema is the representation of the database. Data dictionary, is the storage for the data.
附註：資料模式是基於選定的資料模型對資料進行“型”方面的刻畫，而相應的“例項”則是對資料“值”方面的描述。
這可能時我看到的最好的答案了。我這裡的指代不是很準確，應該說資料字典和資料庫模式有什麼關係？
The schema in a relational database refers to the tables, fields and also the existing relationship between the fields and tables. Schemas are stored in a data dictionary, it is considered as the graphic model of a database.Schema is the representation of the database. Data dictionary, is the storage for the data.
來自：http://www.databaseguides.com/what-is-a-database-schema