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POJPA OneToMany and ManyToOne Relationships
 

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    <p>I have three classes one of the name is User and this user have other classes instances. Like this;</p> <pre><code>public class User{ @OneToMany(fetch=FetchType.LAZY, cascade = CascadeType.ALL) public List&lt;APost&gt; aPosts; @OneToMany(fetch=FetchType.LAZY, cascade = CascadeType.ALL) public List&lt;BPost&gt; bPosts; } public class BPost extends Post { @ManyToOne(fetch=FetchType.LAZY) public User user; } public class APost extends Post { @ManyToOne(fetch=FetchType.LAZY) public User user; } </code></pre> <p>it's working like this but generates emty tables in db. Which have to contains foreign keys. When I tried to use mappedBy and JoinColumn annotains I got failed. How can I resolve this?</p> <p><strong>Extra information:</strong></p> <p>When I changed with;</p> <pre><code> @ManyToOne(fetch=FetchType.LAZY) @JoinColumn(name="id") public User user; </code></pre> <p>and</p> <pre><code> @OneToMany(fetch=FetchType.LAZY, cascade = CascadeType.ALL, mappedBy="id") public List&lt;APost&gt; aPosts; </code></pre> <p>I'm getting</p> <p>A JPA error occurred (Unable to build EntityManagerFactory): Repeated column in mapping for entity: models.post.APost column: id (should be mapped with insert="false" update="false")</p> <p><strong>Final Edit:</strong> Finally, I was totaly wrong about jpa annotaions. :( When i change</p> <pre><code>@OneToMany(fetch=FetchType.LAZY, cascade = CascadeType.ALL, mappedBy="id") </code></pre> <p>to</p> <pre><code>@OneToMany(fetch=FetchType.LAZY, cascade = CascadeType.ALL, mappedBy="user") </code></pre> <p>and</p> <pre><code>@ManyToOne(fetch=FetchType.LAZY) @JoinColumn(name="user_id") </code></pre> <p>everthing works ok. :)</p>
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    1. USÖmer Faruk AK
    1. USÖmer Faruk AK
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      1. USEmily Chen
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    1. COHow exactly did you fail? What are you seeking help with, precisely? And if the first solution worked for you why not stick with it?
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    2. CObecause jpa creates User_APost and User_BPost tables but it's not adding any row to this tables. And it feels me wrong.
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      1. USÖmer Faruk AK
 

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