A BLOB (Binary Large OBject) is a large chunk of data which is stored in a database.

A BLOB differs from regular database data in that it is not forced into a certain structure. A normal database field might be structured to be 14 characters long and only accept lowercase letters. A BLOB field is not usually restricted in content type and content can be several gigabytes in size. Normal database fields have space allocated for them whether they are utilized or not. BLOB fields are only allocated space when they are utilized.

BLOB fields are normally used to store graphics, audio, video, or documents.

BLOB fields can be added, changed, and deleted. However, they cannot be searched and manipulated with standard database commands.BLOB