Changes
Title
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Relations: BELONGS_TO versus HAS_ONE
Category
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FAQs
Yii version
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Tags
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relations, HAS_ONE, BELONGS_TO
Content
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[...]
Relations 3 and 4 are essentially the same thing as each other: the linking field `user_id` is not in **this** model, but in the **related** model, and the primary key involved is in **this** model (`User`). The difference is that `HAS_MANY` returns an array of possibly multiple objects, while `HAS_ONE` returns a single object.
`HAS_ONE` is just a special case of `HAS_MANY`, and the circumstances where `HAS_ONE` makes sense are far more limited than `HAS_MANY` and `BELONGS_TO`.
** Weird example
**
~~~
USER table
- id
- name[...]