Technically you can run inserts and other SQL queries via database layouts, but we'd recommend Select statements only since that is the expected use case that we code and test. The layouts expect to receive a result set (data) back from the SQL query, and depending on which database you're connecting to (and sometimes which driver is used), inserts, creates and deletes don't have any data to return, so the layout (and control) won't have anything to capture due to a null result set. This can cause the layout/control to fail, even though the query was already ran. This holds true even if the query was successful since a result set isn't always returned.