Why is Rowid used?

What is the Rowid?

A row ID is a value that uniquely identifies a row in a table. A column or a host variable can have a row ID data type. A ROWID column enables queries to be written that navigate directly to a row in the table because the column implicitly contains the location of the row. Each value in a ROWID column must be unique.

What is the used of Rowid data types?

A ROWID data type stores information related to the disk location of table rows. They also uniquely identify the rows in your table. The ROWID data type is stored as a hexadecimal. Therefore the hexadecimal string represents the unique address of a row in its table.

How does Rowid help in running a query faster?

ROWID s are the fastest way to access a row of data, but if you can do an operation in a single DML statement, that is faster than selecting the data first, then supplying the ROWID to the DML statement. If rows are moved, the ROWID will change. Rows can move due to maintenance operations like shrinks and table moves.

What is the use of Rowid and Rownum in Oracle?

ROWID helps to retrieve data from a row. ROWNUM allows retrieving a row containing data. ROWID comprises of the position of the row, data object number, the data block in the data file, as well as data file in which row resides. ROWNUM comprises of sequence numbers of the rows.