Oracle gives each record of each table to a unique identification number ROWID it is a pseudo column, does not declare it when defining a table structure, but the system is automatically established. It can't see it when you view the table structure with DESC. This field. With ROWID, the speed is the fastest hours, and Oracle7 and Oracle8 and the following version of RowId are different:
The ROWID of Oracle 7 consists of three parts: block.row.filebbbbbbb.rrr.ffff file number. The line number in the block. The absolute number of the file
oracle 8 8i 9i rowid is composed of four parts: OOOOOOFFFBBBBBBRRROOOOOO: data object number, segment number represents the FFF database table relative file number BBBBBB in space: a file block number of rows in the block position number RRR
Use of RowID data types: RowidTochar: Convert ROWID to a CHAR type.
SELECT ROWIDTOCHAR (A.ROWID) from Testa a where rownum <= 1Aabj3oaeoaaaahpjaaa
Select Chartorowid ('Aabj3oaeoaaahpjaaaa) from Dualaabj3oaeoaaaaaaaaaaaaaaaaaaaa
