Large Object Datatypes
Large objects are most often used to store large amounts (up to 4 gigabytes) of binary data (such as images) or character text data. LOBs have a couple of common characteristics: they typically have sizes that may exceed the limits of other datatypes or formatting that falls outside the understanding of these standard datatypes.
Oracle supports several different datatypes for handling large objects:
- BLOB
Stores up to 4 GBs of binary data. BLOB stands for binary large object. This datatype does not translate values stored in it. It can be used in a transaction.
- CLOB
Stores up to 4 GBs of character data. CLOB stands for character large object. This datatype is used to store a large block of single-byte, fixed-width character data stored inside the database. This datatype does not translate values stored in it. It can be used in a transaction.
- NCLOB
Stores up to 4 GBs of character data. NCLOB stands for National Language Support (NLS) character large object. This datatype does not translate values stored in it. It can be used in a transaction.
- BFILE
The BFILE datatype acts as a pointer to a file stored outside of the Oracle database. Because of this, columns or variables with BFILE datatypes do not participate in transactions, and the data stored in these columns is available only for reading. Oracle treats the data in the outside file as binary data. The file size limitations of the underlying operating system limit the size of data in a BFILE.