newsupernova/vendor/magento/module-variable/etc/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="variable" resource="default" engine="innodb" comment="Variables">
        <column xsi:type="int" name="variable_id" padding="10" unsigned="true" nullable="false" identity="true"
                comment="Variable Id"/>
        <column xsi:type="varchar" name="code" nullable="true" length="255" comment="Variable Code"/>
        <column xsi:type="varchar" name="name" nullable="true" length="255" comment="Variable Name"/>
        <constraint xsi:type="primary" referenceId="PRIMARY">
            <column name="variable_id"/>
        </constraint>
        <constraint xsi:type="unique" referenceId="VARIABLE_CODE">
            <column name="code"/>
        </constraint>
    </table>
    <table name="variable_value" resource="default" engine="innodb" comment="Variable Value">
        <column xsi:type="int" name="value_id" padding="10" unsigned="true" nullable="false" identity="true"
                comment="Variable Value Id"/>
        <column xsi:type="int" name="variable_id" padding="10" unsigned="true" nullable="false" identity="false"
                default="0" comment="Variable Id"/>
        <column xsi:type="smallint" name="store_id" padding="5" unsigned="true" nullable="false" identity="false"
                default="0" comment="Store Id"/>
        <column xsi:type="text" name="plain_value" nullable="true" comment="Plain Text Value"/>
        <column xsi:type="text" name="html_value" nullable="true" comment="Html Value"/>
        <constraint xsi:type="primary" referenceId="PRIMARY">
            <column name="value_id"/>
        </constraint>
        <constraint xsi:type="unique" referenceId="VARIABLE_VALUE_VARIABLE_ID_STORE_ID">
            <column name="variable_id"/>
            <column name="store_id"/>
        </constraint>
        <constraint xsi:type="foreign" referenceId="VARIABLE_VALUE_STORE_ID_STORE_STORE_ID" table="variable_value"
                    column="store_id" referenceTable="store" referenceColumn="store_id" onDelete="CASCADE"/>
        <constraint xsi:type="foreign" referenceId="VARIABLE_VALUE_VARIABLE_ID_VARIABLE_VARIABLE_ID" table="variable_value"
                    column="variable_id" referenceTable="variable" referenceColumn="variable_id" onDelete="CASCADE"/>
        <index referenceId="VARIABLE_VALUE_STORE_ID" indexType="btree">
            <column name="store_id"/>
        </index>
    </table>
</schema>