在两个DB表中有循环引用是一个好习惯 [英] Is it a good practise to have circular reference in two DB tables

问题描述

在我们的DB中，我们有两个具有主键A_id和B_id的表A，B。

在表中使用B_id作为外键是一个好习惯A和A_id作为外键在表B中。这将允许我们在表中具有多对多关系。

另一种方法是使用第三个网桥您认为哪一个是好的做法？

< >解决方案

考虑以下情况

  TableA TableB 
 A 1 
 B 2 
  

如果你想交联这个，你最少需要做表是

  TableA 
 A，1 
 A，2 
 ，1 
 B，2 
 
 TableB 
 1 
 2 
  

对于每个多对多关系，至少有一个表的每一行都重复。

将不会找到许多DBA愿意模仿他们的表。

第三个桥接表真的是这里唯一好的选择。

In our DB we have two tables A, B with primary keys A_id and B_id.

Is it a considered a good practice to have B_id as foreign key in table A and A_id as foreign key in table B. This would allow us to have many-to-many relationship in the table.

An alternative would be to have a third bridge table consisting of just two columns A_id and B_id.

Which one do you think is a good practice?

解决方案

Consider following scenario

TableA  TableB
A       1
B       2

If you want to crosslink this, the least you need to do without creating a third table is

TableA
A, 1  
A, 2   
B, 1
B, 2

TableB
1
2   

Every row of at least one table is duplicated for every many-to-many relationship.

I think you won't find many DBA's willing to model their tables like that.
A third bridge table really is your only good option here.

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