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POIs it possible to have foreign key enforced without object-to-object mapping?
 

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    <p>Assuming the following mappings are provided:</p> <pre><code>&lt;class name="A" table="a_table"&gt; &lt;id name="id"/&gt; &lt;many-to-one name="entityB" column="fk_B" not-null="false" unique="true"/&gt; &lt;/class&gt; &lt;class name="B" table="b_table"&gt; &lt;id name="id"/&gt; &lt;/class&gt; </code></pre> <p>Java class:</p> <pre><code>public class A { private long id; private B entityB; // getters and setters skipped } </code></pre> <p>Is it possible to change the Hibernate mapping so that <strong>foreign key is still enforced and created by Hibernate upon startup</strong>, but class <code>A</code> would look like as the following:</p> <pre><code>public class A { private long id; private long idOfB; // getters and setters skipped } </code></pre> <p>I understand that if I convert <code>&lt;many-to-one...</code> into a <code>&lt;property...</code> this would work, but foreign key would not be enforced by the database.</p> <p>I need to do this because object <code>B</code> might (or might not) be initialized separately which sometimes causes <code>org.hibernate.LazyInitializationException: could not initialize proxy - no Session</code> exceptions to occur when <code>a.getB()</code> is called. I would prefer to have it as a <code>long idOfB</code> and load whole object whenever is necessary; this would also make loading of object <code>A</code> quicker.</p> <p>I believe my question is very similar to <a href="https://stackoverflow.com/questions/743434/hibernate-how-declare-foreign-key-without-having-to-code-association-methods-in">this one</a>, yet the offered solution (to use lazy loading) is not appropriate in my case as even if I call <code>a.getB().getId()</code>, I'd get <code>LazyInitializationException</code> whereas if I call <code>a.getIdOfB()</code> I wouldn't.</p> <p>Thanks very much in advance.</p>
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    1. COI strongly advise to use LazyLoading rather than reinventing the wheel. You'd get type safe entity classes, exactly the same performance, and can potentially do away with custom reloading code. Note that LazyLoading only results in a LazyLoadingException if used incorrectly, i.e. if the lazy load is requested after the session has been closed. Also note that requesting an object's id does not result in the object being loaded. I recommend you post a question with the specific problems you have with LazyLoading.
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    2. COBelieve me, I do use LazyLoading. It's just one case out of hundreds where I can't. Otherwise I wouldn't be asking.
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