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    <p>When you have a List or Set-based collection and you add a new object into your collection, Hibernate will always hit the database because it compare one by one object by using equals implementation before saving or updating - when using a Set - or by comparing a index column when using a List. This behavior is needed because of the Set and List semantic. Because of that, the performance of your application can decrease significantly whether you have a bunch of records.</p> <p>Some workaround to overcome this issue</p> <p><strong>1º</strong> Conversion pattern by using a encapsuled Bag collection plus your desired Set or List exposed as a property</p> <pre><code>@Entity public class One { private Collection&lt;Many&gt; manyCollection = new ArrayList&lt;Many&gt;(); @Transient public Set&lt;Many&gt; getManyCollectionAsSet() { return new HashSet&lt;Many&gt;(manyCollection); } public void setManyCollectionAsSet(Set&lt;Many&gt; manySet) { manyCollection = new ArrayList&lt;Many&gt;(manySet); } /** * Keep in mind that, unlike Hibernate, JPA specification does not allow private visibility. You should use public or protected instead */ @OneToMany(cascade=ALL) private Collection&lt;Many&gt; getManyCollection() { return manyCollection; } private void setManyCollection(Collection&lt;Many&gt; manyCollection) { this.manyCollection = manyCollection; } } </code></pre> <p><strong>2º</strong> Use ManyToOne instead of OneToMany</p> <pre><code>@Entity public class One { /** * Neither cascade nor reference */ } @Entity public class Many { private One one; @ManyToOne(cascade=ALL) public One getOne() { return one; } public void setOne(One one) { this.one = one } } </code></pre> <p><strong>3º</strong> Caching - when applied because of, depending on your requirements, your configuration can increase or decrease the performance of your application. See <a href="http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html_single/#performance-cache-readonly" rel="nofollow noreferrer">here</a></p> <p><strong>4°</strong> SQL constraint - If you want a collection that behaves like a Set, you can use a SQL constraint, which can be applied to a column or <em>set of columns</em>. See <a href="http://www.w3schools.com/sql/sql_unique.asp" rel="nofollow noreferrer">here</a></p>
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    1. POHibernate - How to persist a new item in a Collection without loading the entire Collection
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    1. USArthur Ronald
    1. USArthur Ronald
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    1. COI think it does read the current collection in order to do the add. This is because it needs to check the `Set` constraints. i.e. it needs to see if the entity that you're adding is already in the collection, as it has to return false if it is already there.
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      1. USdavidsheldon
 

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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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