What is ROWID ? What are its components ?
ROWID is the logical address of a row, and it is unique within the database.The ROWID is broken into three sections: left,middle,, and right (corresponding to 00001F20,000C, AND 0001, just shown). The numbering is in hexadecimal notation.
The left section is the block in the file, the middle is the row sequence number within the block(numbering starts with 0, not 1), and the right is the file number within the database. Note that the file numbers are uniquewithin the whole database. The tablespace they are in is not relevant to the ROWID.
ROWID can be selected, or used in a where clause, but cannot be changed by an insert, update, or delete. However it can changeif the table it is in is exported and imported.
