ALTER TABLE might not produce consistent results when used with Visual FoxPro cursors created by the CREATE CURSOR command. In particular, you can create a Visual FoxPro cursor with features, such as long field names, that are normally available only with tables that are part of a database container. ALTER TABLE saves a temporary copy of the cursor, so the rules that apply to free tables also apply, and any features requiring database support are lost or changed in an unpredictable manner. Therefore, you should generally avoid using ALTER TABLE with Visual FoxPro cursors unless you have tested and understood the outcome.