Accessing object
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Thread: Accessing object

  1. #1
    Join Date
    Sep 2002
    Posts
    376
    Hi everybody,

    I just wanted to know, when we issue a sql
    statement how oracle finds the location of
    the block in the hard disk.(Assuming no index
    is built on the table)
    Does it store any information of about the object
    in the dictionary ? I think rowid is not stored
    anywhere, then how oracle searches for the object

    Thanks in advance

  2. #2
    Join Date
    Sep 2000
    Location
    Chennai, India
    Posts
    865

  3. #3
    Join Date
    Feb 2001
    Location
    Bombay,India
    Posts
    530
    Hi,
    Oracle does stores the ROWID in its data-dictonary.Oracle finds the location of block using extended ROWID's which is new in Oracle 8 and above.Extended ROWID's consists of the following components:



    e.g.
    ROWID: AAABPWAAFAAAAv1AAA
    where AAABPW is objectno
    AAF is relative file no
    AAAAv1 is blockno
    AAA is rownum

    Regards,
    Rohit Nirkhe,Oracle/Apps DBA,OCP 8i






    Originally posted by bang_dba
    Hi everybody,

    I just wanted to know, when we issue a sql
    statement how oracle finds the location of
    the block in the hard disk.(Assuming no index
    is built on the table)
    Does it store any information of about the object
    in the dictionary ? I think rowid is not stored
    anywhere, then how oracle searches for the object

    Thanks in advance
    Thanks and Regards
    Rohit S Nirkhe
    rohitsnirkhe@rediffmail.com

  4. #4
    Join Date
    Sep 2002
    Posts
    376
    hi rhohit
    I don't think it is possble for oracle to store rowids
    of all the rows in the dictionary, that would consume
    lot of space....

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