有时表列不归主键,但仍然独一无二要标记为独一性,你必须创建替代(独一性)密钥内含它
单列备用密钥
选择单列表并点击替代(唯一)密钥标签内表属性右侧面板
![选择表内列自定义独栏并扩展右表属性面板中复用键段](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-alternate-unique-key-1.png)
点击添加密钥:
![点击添加密钥,备用密钥](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-alternate-unique-key-2.png)
点击下向箭头显示属性 :
![下向箭头显示属性](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-alternate-unique-key-3.png)
查找列拟独创并添加到密钥上
![查找右列并添加到密钥独列](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-alternate-unique-key-4.png)
列独特性
![列设置为独一独列](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-alternate-unique-key-5.png)
可点击表代码检查SQL预览右顶角按钮 :
![可见SQL代码预览中你独有密钥](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-alternate-unique-key-6.png)
多列备用密钥
唯一密钥可能多列创建多列单选表扩展替代(唯一)密钥右侧段并点击添加密钥:
![创建多列独有密钥,选择表,扩展右侧的复用密钥段,并点击加密](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-a-multicolumn-alternate-unique-key-1.png)
添加所有列拟包括在您的密钥中 :
![添加所有您想包含到唯一密钥中的列](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-a-multicolumn-alternate-unique-key-2.png)
多列备用密钥准备就绪(见SQL代码预览):
![多列备用密钥备妥](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-add-a-multicolumn-alternate-unique-key-3.png)
设置索引为唯一
索引独有性刚去索引:
![扩展索引属性](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-set-an-index-as-unique-1.png)
点击集成邻接唯一字段 :
![点击unique域旁的'set'](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-set-an-index-as-unique-2.png)
并设置对:
![确定unique字段设置为s](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-set-an-index-as-unique-3.png)
SQL预览你独有索引显示如下:
![sql预览你独有索引](//www.alan-ioth.com/blog/database-modeling-tip-4-how-to-make-a-column-unique/how-to-set-an-index-as-unique-4.png)