what is the difference between data file and data block in oracle I'd like to know if there is any difference between the data block which is the  smallest logical unit of data storage in Oracle Database and the data file which is a physical file on disk that was created by Oracle Database and contains the data for a database?

Can anybody please tell me that what exactly difference between the data file and the data block?
The Logical Storage Structures section in the Oracle Concepts Guide has a good explanation of both data blocks and data files (pages 259 - 296).  There is quite a bit of good information including illustrations, but here are some excerpts:


  data block 
  Smallest logical unit of data storage in Oracle Database.
  Other names for data blocks include Oracle blocks or pages. One data
  block corresponds to a specific number of bytes of physical space on
  disk.
  
  data file
  A physical file on disk that was created by Oracle Database
  and contains the data for a database. The data files can be located
  either in an operating system file system or Oracle ASM disk group.