Bigfile Tablespace Rowid Format

In a bigfile tablespace, there is only one file that always has a relative file number of 1024. A bigfile tablespace has a three-piece format, OOOOOOLLLLLLLLLRRR, in which

LLLLLLLLL is used to denote the block number. The concatenation of FFF and BBBBBB makes the encoded block number. For BFTs, the only supported way of getting components of extended rowids is to use the Oracle DBMS_ROWID package.

Here is an example on how to use the Oracle dbms_rowid package to retrieve rowid information:

select dbms_rowid. rowid_relative_fno(rowid, 'BIGFILE')
bigfile_rowid,
dbms_rowid. rowid_relative_fno(rowid, 'SMALLFILE')
smallfile_rowid,
first_name, last_name
FROM hr.employees
where rownum < 3;

BIGFILE_ROWID SMALLFILE_ROWID FIRST_NAME LAST_NAME

------------- --------------- -------------------- ---------

1024 4 Ellen Abel

1024 4 Sundar Ande

The rowid can be easily manipulated with the Oracle DBMS_ROWID package (.If, against Oracle admonitions not to, you used rowid in your Oracle7 application, you will have to familiarize yourself with this package..

Old rowids (called restricted rowids) will be automatically converted to the new format if:

You use export/import to move data.

You use the migration utility.

You use the ODMA to upgrade to 9i.

If you used rowids in your Oracle7 application and stored them as columns in other tables, then these columns will have to be manually changed to the new format using the Oracle DBMS_ROWID package. If a column in a table has been designated as a datatype of rowid, it will be altered to accept the new format during migration; this will not affect the data in the column.