Classes/Console/Database/Schema/SchemaUpdate.php
public function getDestructiveUpdates()
    {
        $sqlStatements = $this->sqlReader->getCreateTableStatementArray($this->sqlReader->getTablesDefinitionString());
        // Difference from current to expected
        $dropRename = $this->schemaMigrator->getUpdateSuggestions($sqlStatements, true);

        // Aggregate the per-connection statements into one flat array
        return array_merge_recursive(...array_values($dropRename));
    }
public function getDestructiveUpdates()
    {
        $sqlStatements = $this->sqlReader->getCreateTableStatementArray($this->sqlReader->getTablesDefinitionString());
        // Difference from current to expected
        $dropRename = $this->schemaMigrator->getUpdateSuggestions($sqlStatements, true);

        // Aggregate the per-connection statements into one flat array
        return array_merge_recursive(...array_values($dropRename));
    }
Get all schema updates that are destructive (renaming/ deleting fields/ tables)

@return array