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关系数据库，多对多(Relationship Database, many to many)

 我如何在关系数据库（例如MySQL）中表示如下情况：  
 1）单个用户可以是许多不同事件的组织者  
 2）一个活动只能有一个组织者  
 3）和事件可以有很多参与者（都在用户表之间）  
 4）用户可以参与许多事件（只有当事件从头到尾不与另一事件发生冲突时）  
 这里是DB的草图，我必须理解这种多对多的关系。  

How do I represent, as a diagram, in a relationship database (eg MySQL ) the case in which: 
1) a single user can be the organizer of many different events 
2) an event can have only one organizer 
3) and event can have many participants (which are all between the Users Table) 
4) a user can participate to many event (Only if the event does not collide to another event from start to end) 
here is a sketch of the DB, I have to understand this many to many relationship.

原文：https://stackoverflow.com/questions/40420184

更新时间：2023-10-13 22:10

最满意答案

 UIButton的工作方式与UILabel不同。 他们有一个控制状态 。 并且可以在每个控制状态的基础上设置它们的（标题）文本。  
 所以你必须使用currentTitle属性：  
 https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIButton_Class/#//apple_ref/occ/instp/UIButton/currentTitle  
 或titleForState方法：  
 https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIButton_Class/#//apple_ref/occ/instm/UIButton/titleForState ：  
 现在这些标题是普通的String对象; 这是不同的财产的名称。 

UIButtons simply work differently than UILabels. They have control states for one thing. And their (title) text can be set on a per-control-state basis. 
So you have to use the currentTitle property: 
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIButton_Class/#//apple_ref/occ/instp/UIButton/currentTitle 
or the titleForState method: 
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIButton_Class/#//apple_ref/occ/instm/UIButton/titleForState: 
Now those titles are normal String objects; it's the name of the property that's different.

关系数据库，多对多(Relationship Database, many to many)

最满意答案

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