The document provides instructions on how to rename a data file in an Oracle database, distinguishing between system tablespace and non-system tablespace procedures. For system files, one must shut down the database, rename the file, and restart it; for non-system files, one can take the tablespace offline, rename the file, and bring it back online without shutting down the entire database. It emphasizes that the rename commands in Oracle only change pointers in the control file, not the actual file names in the operating system.