Other Scalar Datatypes
Oracle also supports a number of specialized datatypes:
- BOOLEAN
Holds a Boolean value (TRUE, FALSE, or NULL).
- RAW and LONG RAW
Normally, the Oracle database server not only stores data, but also interprets that data. When data is exported from the database or requested from the database, the Oracle database sometimes needs to convert the character set or perform blank padding on the data.
The RAW and LONG RAW datatypes circumvent any interpretation on the part of the Oracle database. When you specify one of these datatypes, Oracle will store the data as the exact series of bytes presented to it. The RAW datatypes typically store objects with their own internal format, such as bitmaps. A RAW datatype can hold 2000 bytes, while a LONG RAW datatype can hold 2 GBs.
- ROWID
The ROWID is a special type of column known as a pseudocolumn. The ROWID pseudocolumn can be accessed just like a column in a SQL SELECT statement. There is a ROWID pseudocolumn for every row in an Oracle database. The ROWID represents the specific address of a particular row. You can define the ROWID pseudocolumn with a ROWID datatype.
The ROWID relates to a specific location on a disk drive. For this reason, the ROWID is the fastest way to retrieve an individual row. However, the ROWID for a row can change as the result of dumping and reloading the database. As a consequence, we don’t recommend using the value for the ROWID pseudocolumn across transaction boundaries.
You cannot set the value of the standard ...