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【单选题】
如何在已经创建好的表上添加一个外键约束: 。A.
alter table 表名 add constraint foreign key (键名) references 关联表（关联键名）
B.
alter table 表名 add primary key (键名) references 关联表（关联键名）
C.
alter table 表名 add foreign key (键名) references （关联键名）
D.
alter table 表名 add constraint primary key (键名) references 关联表（关联键名）
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皮皮学刷刷变学霸
举一反三
【单选题】E There were smiling children all the way. Charily they knew at what time the train passed their homes and they made it their business to stand along the railway, wave to complete strangers and cheer ...
A.
adventurou s
B.
pleasant
C.
exciting
D.
dull
【简答题】旋毛形线虫的成虫主要寄生于猪()。 A肺脏 B小肠 C肝脏 D心肌
【简答题】A There were smiling children all the way. Charily they knew at what time the train passed their homes and they made it their business to stand along the railway, wave to complete strangers and cheer ...
【简答题】旋毛形线虫的成虫主要寄生在人体的( )内。
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