Advanced Oracle PL/SQL Developer's Guide - Second Edition

LOB data types in Oracle

Oracle provides four data types dedicated for declaring large objects, namely: BLOB, CLOB, NCLOB, and BFILE.

BLOB and CLOB

There are three types of internal LOB data types, namely:

• BLOB: The Binary Large Object data type is used to store large binary files that cannot be logically broken down to data bits such as PDFs, images, audios or videos, and so on.
• CLOB: The Character Large Object data type stores the single-byte character data in the database character set format. It supports fixed-width character formats.
• NCLOB: The CLOB data type that can store national character set data and support varying width format character sets.

Note

Starting from Oracle 10g, Oracle can cast the CLOB data to the VARCHAR2 data implicitly.

BFILE ...