4.2. Database objects

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Hibernate allows you to customize the schema generation process via the HBM `database-object` element.

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Considering the following HBM mapping:

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<div id="schema-generation-database-object-example" class="exampleblock">
<div class="title">Example 216. Schema generation HBM database-object</div>
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<div class="listingblock">
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<pre class="prettyprint highlight">`&lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd" &gt;

&lt;hibernate-mapping&gt;
    &lt;database-object&gt;
        &lt;create&gt;
            CREATE OR REPLACE FUNCTION sp_count_books(
                IN authorId bigint,
                OUT bookCount bigint)
                RETURNS bigint AS
            $BODY$
                BEGIN
                    SELECT COUNT(*) INTO bookCount
                    FROM book
                    WHERE author_id = authorId;
                END;
            $BODY$
            LANGUAGE plpgsql;
        &lt;/create&gt;
        &lt;drop&gt;&lt;/drop&gt;
        &lt;dialect-scope name="org.hibernate.dialect.PostgreSQL95Dialect" /&gt;
    &lt;/database-object&gt;
&lt;/hibernate-mapping&gt;`</pre>
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<div class="paragraph">

When the `SessionFactory` is bootstrapped, Hibernate is going to execute the `database-object`, therefore creating the `sp_count_books` function.

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<div class="sect2">