gistfile1.xml

<?xml version="1.0" ?>
<constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping
        http://symfony.com/schema/dic/services/constraint-mapping-1.0.xsd">


    <class name="Application\Sonata\NewsBundle\Entity\Post">
        <getter property="title">
            <constraint name="NotBlank" />
            <constraint name="NotNull" />
        </getter>

        <getter property="abstract">
            <constraint name="NotNull" />
            <constraint name="NotBlank" />
        </getter>

        <getter property="author">
            <constraint name="Valid" />
        </getter>

        <getter property="content">
            <constraint name="NotNull" />
            <constraint name="NotBlank"/>
        </getter>

        <getter property="tags">
            <constraint name="Valid" />
        </getter>
    </class>

    <class name="Application\Sonata\NewsBundle\Entity\Comment">
        <getter property="name">
           <constraint name="NotBlank" />
           <constraint name="NotNull" />
        </getter>

        <getter property="email">
            <constraint name="NotNull" />
            <constraint name="NotBlank" />
            <constraint name="Email" />
        </getter>

        <getter property="url">
           <constraint name="Url" />
        </getter>

        <getter property="message">
            <constraint name="NotNull" />
            <constraint name="NotBlank" />
        </getter>

        <!--<getter property="post">-->
            <!--<constraint name="Valid" />-->
        <!--</getter>-->

    </class>

    <class name="Application\Sonata\NewsBundle\Entity\Tag">
        <getter property="name">
           <constraint name="NotBlank" />
           <constraint name="NotNull" />
        </getter>
    </class>

</constraint-mapping>