Magento 2: Many-to-Many-Relationship - db_schema

# Magento 2 - Many-to-Many-Relationship - db_schema.md

Magento 2 - Many-to-Many-Relationship

db_schema

etc\db_schema.xml

<?xml version="1.0"?>
<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">

    ...
        
    <table name="custom_blog_product_blog_relation" resource="default" engine="innodb" comment="Product to Blog Relation Table">
        <column xsi:type="int" name="relation_id" padding="10" identity="true"
                unsigned="true" nullable="false" comment="Entity ID"/>
        <column xsi:type="int" name="product_id" padding="10" identity="false"
                unsigned="true" nullable="false" comment="Related Product ID"/>
        <column xsi:type="int" name="blog_id" padding="10" identity="false"
                unsigned="true" nullable="false" comment="Related Blog ID"/>
        <constraint xsi:type="primary" referenceId="PRIMARY">
            <column name="relation_id"/>
            <column name="product_id"/>
            <column name="blog_id"/>
        </constraint>
        <constraint xsi:type="foreign" referenceId="PROD_BLOG_REL_PROD_ID_PROD_ID"
                    table="custom_blog_product_blog_relation" column="product_id"
                    referenceTable="catalog_product_entity" referenceColumn="entity_id"
                    onDelete="CASCADE"/>
        <constraint xsi:type="foreign" referenceId="PROD_BLOG_REL_BLOG_ID_BLOG_ID"
                    table="custom_blog_product_blog_relation" column="blog_id"
                    referenceTable="custom_blog" referenceColumn="blog_id"
                    onDelete="CASCADE"/>
        <constraint xsi:type="unique" referenceId="PROD_BLOG_REL_PROD_ID_BLOG_ID_KEY">
            <column name="product_id"/>
            <column name="blog_id"/>
        </constraint>
        <index referenceId="PROD_BLOG_REL_PROD_ID_INDEX" indexType="btree">
            <column name="product_id"/>
        </index>
    </table>
    
    ...
    
</schema>