单个外键引用同一表中的多个列 [英] Single Foreign Key Referencing Multiple Columns in Same Table
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问题描述
一个表的主键可以多次成为另一个表中的外键。请看下面的场景:
表:1
id(pk)
title
referenceID(FK)
oldreferenceID(FK)
表:2
referenceID(PK)
referenceTitle
在这里,我可以使用表:2 referenceID(PK)作为表:1 referenceID(FK)& oldreferenceID(FK)中的外键?
请指教。在此先感谢。
解决方案
是的,它绝对有效,一个表可以在几列中引用相同的主键。
是。这很正常 - 想想地址,例如:公司可能有一个账单地址和一个送货地址。您只需存储一次地址,并使用外键引用将它们附加到单个公司。每个地址都有一个不同的主键。
这可能对你有帮助:
http://stackoverflow.com/questions/18248366 / trigger-on-delete-on-update-for-table-with-many-columns-that-to-one-co [ ^ ]
Can a primary key of one table be a foreign key in another table more than one time. Please see the scenario below:
Table:1
id (pk)
title
referenceID (FK)
oldreferenceID (FK)
Table:2
referenceID (PK)
referenceTitle
Here, can i use "Table:2 referenceID (PK)" as foreign key in "Table:1 referenceID (FK) & oldreferenceID (FK) ?"
Please advise. Thanks in advance.
解决方案
Yes, it is absolutely valid, a table can reference the same primary key in several columns.
Yes. It's pretty normal - think of addresses for example: a company may have a Billing address and a Delivery Address. You would only store each address once, and use Foreign Key references to attach them to the single company. Each address would have a distinct Primary Key.
This maybe help you :
http://stackoverflow.com/questions/18248366/trigger-on-delete-on-update-for-table-with-many-columns-that-reference-to-one-co[^]
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