db_schema.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">
    <table name="training" resource="default" engine="innodb" comment="Training Helloworld">
        <column xsi:type="smallint" name="id" padding="6" unsigned="false" nullable="false" identity="true" comment="ID"/>
        <column xsi:type="varchar" name="name" nullable="false" length="25" comment="Name"/>
        <column xsi:type="varchar" name="email" nullable="false" length="25" comment="Email"/>
        <column xsi:type="varchar" name="description" nullable="false" length="255" comment="Descrition"/>
        <constraint xsi:type="primary" referenceId="PRIMARY">
            <column name="id"/>
        </constraint>
    </table>
</schema>