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?

  • A data file contains many, many data blocks
    – user1822
    Jan 22, 2015 at 9:00
  • I usually don't link answers like "read the documentation" but in this case this is the only answer I have.
    – o0x258
    Jan 22, 2015 at 17:31
  • Weird question. So, you're asking what is the difference between a logical and a physical component (which you mention yourself already). One is logical, the other is physical. Please rephrase your question to a serious question, if you want a serious answer.
    – tvCa
    Jan 25, 2015 at 13:31

1 Answer 1


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.

  • I think this link to the manual is better: docs.oracle.com/database/121/CNCPT/logical.htm#CNCPT004
    – user1822
    Jan 22, 2015 at 14:30
  • @a_horse_with_no_name Both my link and yours point to the 12c Concepts Guide. The difference is that mine is to the pdf and yours is to the web documentation - each useful depending on how it needs to be consumed. Jan 22, 2015 at 17:34

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