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Image, Audio, and Video Extenders Administration and Programming

Large objects

DB2 allows you to store large objects (LOBs) in a database as:

BLOBs are binary strings. Image, audio, and video objects are stored as BLOBs in a DB2 database. CLOBs are character strings made up of single-byte characters with an associated code page. This data type is used for text objects that contain single-byte characters. DBCLOBs are character strings made up of double-byte characters with an associated code page. This data type is used for text objects where double-byte characters are used.

Each LOB can be up to two gigabytes in length; however, DB2 allows many LOB columns per table. You can store up to 24 gigabytes of LOB space per row and up to 4 terabytes of LOB space per table.

Because of its size, a LOB's content is not directly stored in the user's table. Instead each LOB is identified in the table by a large object descriptor. The descriptor is used to access the large object stored elsewhere on the disk.

The DB2 extenders give you the added flexibility of keeping the content of a LOB in a file and pointing to it from the database. You make this designation when you use a DB2 extender to store an object.


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