PostgreSQL 8.3.5 Documentation

Chapter 31. Large Objects

Table of Contents

31.3.1. Creating a Large Object
31.3.2. Importing a Large Object
31.3.3. Exporting a Large Object
31.3.4. Opening an Existing Large Object
31.3.5. Writing Data to a Large Object
31.3.6. Reading Data from a Large Object
31.3.7. Seeking in a Large Object
31.3.8. Obtaining the Seek Position of a Large Object
31.3.9. Truncating a Large Object
31.3.10. Closing a Large Object Descriptor
31.3.11. Removing a Large Object

PostgreSQL has a large object facility, which provides stream-style access to user data that is stored in a special large-object structure. Streaming access is useful when working with data values that are too large to manipulate conveniently as a whole.

This chapter describes the implementation and the programming and query language interfaces to PostgreSQL large object data. We use the libpq C library for the examples in this chapter, but most programming interfaces native to PostgreSQL support equivalent functionality. Other interfaces might use the large object interface internally to provide generic support for large values. This is not described here.