Reserved words are part of the Firebird SQL language. They cannot be used as identifiers (e.g. as table or procedure names), except when enclosed in double quotes in Dialect 3. However, you should avoid this unless you have a compelling reason.

Keywords are also part of the language. They have a special meaning when used in the proper context, but they are not reserved for Firebird's own and exclusive use. You can use them as identifiers without double-quoting.

The following sections present the changes since InterBase 6. Full listings of Firebird 2.5 reserved words and keywords can be found in the Appendix.