[英]Rails belongs_to vs parent_id
Generic active record questions: 常规活动记录问题:
- Advantages/disadvantages of belongs_to association vs a parent_id column? -相对于parent_id列的belongs_to关联的优缺点?
- Conventions regarding the 2? -关于2的约定?
- Does belongs_to association enforce :null => false
? -belongs_to关联是否执行
:null => false
?
class CreateIssues < ActiveRecord::Migration
def change
create_table :issues do |t|
t.belongs_to :project
t.timestamps
end
end
VS VS
class CreateIssues < ActiveRecord::Migration
def change
create_table :issues do |t|
t.integer :project_id, :null => false
t.timestamps
end
end
Thanks alot! 非常感谢!
belongs_to() is just an alias to references(), which does not enforce the (:null => false) condition. nobody_to()只是references()的别名,不会强制执行(:null => false)条件。 Check out the source .
查看源代码 。
I find it's more common to use references(), but again, belongs_to() is a valid alias. 我发现使用references()更常见,但是再次,belongs_to()是有效的别名。
It's uncommon to see the reference written out manually, as its part of the way ActiveRecord simplifies these associations. 手动写出引用是不常见的,因为它是ActiveRecord简化这些关联的一部分。
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