1.3 Where Should We Use LOBs?

Large objects are suitable for semistructured and unstructured data.

Large object features enable you to store the following types of data in the database and also in the operating system files that are accessed from the database.

• Semistructured data

  Semistructured data has a logical structure that is not typically interpreted by the database, for example, an XML document that your application or an external service processes. Oracle Database provides features such as Oracle XML DB, Oracle Multimedia, and Oracle Spatial and Graph to help your application work with semistructured data.

• Unstructured data

  Unstructured data is easily not broken down into smaller logical structures and is not typically interpreted by the database or your application, such as a photographic image stored as a binary file.

Data unsuited for LOBs

• Simple Structured Data

  Simple structured data can be organized into relational tables that are structured based on business rules.

• Complex Structured Data

  Complex structured data is suited for the object-relational features of the Oracle Database such as collections, references, and user-defined types.

Maximum Size of a LOB

The maximum permissible LOB size for your configuration depends on the block size setting of the tablespace. It is calculated as (4 gigabytes - 1)*(space usable for data in the LOB block). For example, if a LOB is stored in a tablespace of block size 8K, then the approximate maximum LOB size is about 32 terabytes.