A rowid is an internal representation of the storage location of data.The rowid of a row specifies the data file and data block containing the row and the location of the row in that block.Locating a row by specifying its rowid is the fastest way to retrieve a single row because it specifies the exact location of the row in the database.
To access a table by rowid, database performs the following steps:
1.Obtains the rowids of the selected rows, either from the statement WHERE clause or through an index scan of one or more indexes
Table access may be needed for columns in the statement not present in the index.
2.Locates each selected row in the table based on its rowid
To access a table by rowid, database performs the following steps:
1.Obtains the rowids of the selected rows, either from the statement WHERE clause or through an index scan of one or more indexes
Table access may be needed for columns in the statement not present in the index.
2.Locates each selected row in the table based on its rowid
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