表中有多少主要的外键使用？ [英] how many primary ,foregin key use in a table?

问题描述

表中使用了多少个主要的外包密钥？

推荐答案

你的问题不太清楚，但是我会尝试给你一些答案......

任何给定的表可以是一个，只有一个主键，并且该键永远是唯一的...

外键是从THIS表指向OTHER表的主键的键。从理论上讲，您可以拥有任意数量的外键，但建议您不要超过253 ......

请参阅此表有关SQL的功能：https://msdn.microsoft.com/en-us/library/ms143432(v=sql.105）。 aspx [ ^ ]

Your question is not too clear, however I will try and give you some answers...
Any given table can be one, and only one, primary key, and that key will always be unique...
A foreign key is a key that point from THIS table to a primary key of an OTHER table. In theory you can have as many foreign keys as you want, but it is recommended that you do not exceed 253...
See this table about capabilities of SQL:https://msdn.microsoft.com/en-us/library/ms143432(v=sql.105).aspx[^]

sql server capacity specifications [ ^ ]



这表明您可以使用无限制的forgein键，但建议不要超过253。

sql server capacity specifications [^]

This shows that you can have unlimited forgein keys but are recommended not to exceed over 253.

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