Overview

Some data cartridges need to handle large amounts of raw binary data, such as graphic images or sound waveforms, or character data, such as text or streams of numbers. Oracle8i supports large objects (LOBs) to handle these kinds of data.

Internal LOBs are stored in the database tablespaces in way that optimizes space and provides efficient access. Internal LOBs participate in the transactional model of the server. External LOBs are stored in operating system files outside the database tablespaces. External LOBs do not participate in transactions.

Internal LOBs can store binary data (BLOBs), single-byte character data (CLOBs), or fixed-width single-byte or multibyte character data (NCLOBs). An NCLOB consists of character data that corresponds to the national character set defined for the Oracle database. Varying-width character data is not supported in Oracle8i. External LOBs store only binary data (BFILEs). Together, internal and external LOBs provide considerable flexibility in handling large amounts of data.

Data stored in a LOB is called the LOB's value. To the Oracle8i server, a LOB's value is unstructured and cannot be queried. You must unpack and interpret a LOB's value in cartridge-specific ways.

LOBs can be manipulated using the Oracle Call Interface (OCI) or the PL/SQL DBMS_LOB package. You can write functions (including methods on object types that can contain LOBs) to manipulate parts of LOBs. Details on LOBs can be found in the Oracle8i Application Developer's Guide - Large Objects (LOBs).