The data file header contains metadata about a data file: Size of the data file. ... Absolute file number that uniquely identifies the data file in the database. Relative file number that uniquely identifies the data file in the tablespace that it belongs to.

What is a datafile in Oracle?

Datafiles are physical files of the operating system that store the data of all logical structures in the database. They must be explicitly created for each tablespace. Oracle assigns each datafile two associated file numbers, an absolute file number and a relative file number, that are used to uniquely identify it.

What is the use of datafile in Oracle?

Data files are the operating system files that store the data within the database. The data is written to these files in an Oracle proprietary format that cannot be read by other programs. Tempfiles are a special class of data files that are associated only with temporary tablespaces.