The physical structure of an Oracle database is determined by the operating system files that provide the actual physical storage for database information.One characteristic of an RDBMS is the independence of logical data structures such as tables, views, and indexes from physical storage structures. Because physical and logical structures are separate, you can manage physical storage of data without affecting access to logical structures. For example, renaming a database file does not rename the tables stored in it. An Oracle database is a set of files that store Oracle data in persistent disk storage.The physical structure of an Oracle database includes only three types of files: control files, data files, and redo log files
Data files
A data file is a physical file on disk that was created by Oracle Database and contains data structures such as tables and indexes. A temp file is a data file that belongs to a temporary tablespace. The data is written to these files in an Oracle proprietary format that cannot be read by other programs.
Control files
A control file is a root file that tracks the physical components of the database.
Online redo log files
The online redo log is a set of files containing records of changes made to data.
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