JPA associations implementation difference in bidirectional and uni directional

Question

• I have two Model classes.I am trying to make those two classes with associated classes.
• When I explored the implementation , I read that these association can be bidirectional or uni directional.
• Bidirectional entity class containing association annotations in both class and in the case of uni directional association annotation is only in one class.
• So when I am going to make associated classes for relation, How I will identify or decide where I need to use bidirectional implementation and where I need to use uni directional ? What is its implementation deviation? Can anyone help me to identify this??

Answer 1

Lets take an example where in one entity A is mapped to many entity B

1. If you will be fetching data for/querying from entity A and wont ever need to fetch from entity B the going for unidirectional One-to-Many mapping makes sense.
2. But if you would be querying from entity A as well as from entity B it is recommended to go for bidirectional One-To-Many