PL/SQL: LOB’S

Large Objects (LOBs) are a set of datatypes that are designed to hold large amounts of data. A LOB can hold up to a maximum size ranging from 8 terabytes to 128 terabytes depending on how your database is configured. Storing data in LOBs enables you to access and manipulate the data efficiently in your application.

This section introduces different types of data that you encounter when developing applications and discusses which kinds of data are suitable for large objects.

In the world today, applications must deal with the following kinds of data:

• Simple structured data.

This data can be organized into simple tables that are structured based on business rules.

• Complex structured data

This kind of data is complex in nature and is suited for the object-relational features of the Oracle database such as collections, references, and user-defined types.

• Semi-structured data

This kind of data has a logical structure that is not typically interpreted by the database. For example, an XML document that is processed by your application or an external service, can be thought of as semi-structured data. The database provides technologies such as Oracle XML DB, Advanced Queueing, and Messages to help your application work with semi-structured data.

• Unstructured data

This kind of data is not broken down into smaller logical structures and is not typically interpreted by the database or your application. A photographic image stored as a binary file is an example of unstructured data.

Large objects are suitable for these last two kinds of data: semi-structured data and unstructured data. Large objects features allow you to store these kinds of data in the database as well as in operating system files that are accessed from the database.

With the growth of the internet and content-rich applications, it has become imperative that the database support a datatype that:

• Can store unstructured and semi-structured data in an efficient manner.
• Is optimized for large amounts of data.
• Provides a uniform way of accessing data stored within the database or outside the database.