C/SiC复合材料数据库的逻辑结构设计

C／SiC复合材料数据库对在材料研究过程中获得的全部信息实现可靠、高效的存储和访问。在遵守关系数据库第3范式的基础上，基于Oracle的支持，采用了非第1范式的对象数据类型——嵌套表，建立了对象一关系数据库，并利用UML语言完成数据库逻辑建模。根据应用需求定义了用户视图，制定了数据规范、约束、触发器等以保证数据的完整性和一致性。数据库保证了研究信息的可追溯性，为数据的管理和规范提供了有力的工具。

Logic Structure Design of the Database for C/SiC Composite Materials

To realize the optimized design of C/SiC composite materials, a database is developed to investigate the relationships among the synthesizing process, microstructure and mechanical properties of this type of materials. The database stores all information gathered during every stage of the research, and provides a reliable and efficient platform for the data access and handling. To ensure that the influencing factors on the properties are traceable, the logic structure of the database is elaborately designed. The object-relational model is utilized and the 3rd normal form is obeyed. Supported by Oracle 9i, an object data model, named nested table, which is non-1st normal form, is used to meet the need of the complex information type and to promote the system efficiency. The logic structure is modeled by the unified modeling language (UML). The data specification, constraints and triggers are defined to guarantee the data integrity and consistency. User views are designed according to the application demands. The database guarantees the data integrity and traceability and provides a powerful tool to standardize and manage the research information.