是计算所买书籍的价钱,总共价钱的。输入单价和本数,则计算出总的价钱。-is calculated by the price of buying books, the total price. Input price and the number, then calculate the total price.
三种典型的数据库系统( 关系、层次、网状)
关系数据库标准SQL
关系数据库理论
数据库设计
数据库的安全保护
数据库新技术发展
-Three typical database system (the relationship between the level of mesh) relational database standard SQL relational database theory database design database security protection database development of new technologies