According to @Anton's answer, database updates are applied by PHP code in the Magento modules themselves.
(, DOCROOT\app\code\core\Mage\Catalog\), sql\modulename_setup, , , .
, ( etc/config.xml ) Magento, , Mage_Catalog, .
- Magento core_resource mysql. , config.xml, Magento sql\modulename_setup, data_version version.
sql DDL, DML, , , .
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