数据库英文练习数据模型图

来源：百度知道 编辑：UC知道 时间：2024/05/27 04:36:28
An exercise: Each building in an organization has a different BUILDING-NAME and a BUILDING-ADDRESS. The meeting rooms have their own ROOM-NO and each room has a SEATING CAPICITY. Rooms are available for rent for meetings. Meetings must start on the hour. The HOUR and LENGTH-OF-USE are recorded. Groups renting the rooms have a GROUP-NO and a CONTACT-PHONE. Equipment such as overhead projectors can also be rented with the room. Each piece of equipment has an EQUIP-NO and a DESCRIPTIION. Make an E-R diagram of this situation and map it to relational tables.

building （in） organization
building有不同的BUILDING-NAME和一个BUILDING-ADDRESS（可以相同）
rooms有自己的ROOM-NO（唯一的号），每个room有一个SEATING CAPICITY（每个唯一号）romms 可以用来 rent和meetings
meetings 必须按小时计算 HOUR and LENGTH-OF-USE 是已记录的
GROUPS 租 这些rooms有GROUP-NO和CONTACT-PHONE
Equipment设备譬如overhead projectors可以跟room一起出租
每个equipment含有EQUIP-NO和DESCRIPTIION
画E-R图 标注关系表
organization ---building（BUILDING-NAME【unipue】，BUILDING-ADDRESS）
building ---rooms (ROOM-NO【unipue】，SEATING CAPICITY【unipue】)---{rent meetings}---<equipment(EQUIP-NO,DESCRIPTIION)>
---meetings(HOUR,LENGTH-OF-USE)

什么意思