Worked on the zendesk/maxwell repository to deliver support for DDL IF EXISTS and IF NOT EXISTS clauses in MariaDB and MySQL, focusing on safer schema migrations. Extended the SQL grammar using ANTLR and Java to handle these clauses in ALTER TABLE and INDEX statements, ensuring correct syntax and placement. Developed and integrated targeted tests to verify safe handling of database objects that may not exist, reducing the risk of deployment errors. This work improved the reliability of schema changes and strengthened continuous integration coverage, demonstrating a disciplined approach to grammar correction, SQL parsing, and database management within a short project period.