Binary large object
A Binary Large OBject (BLOB) is a collection of binary data stored as a single entity in a database management system. Blobs are typically images, audio or other multimedia objects, though sometimes binary executable code is stored as a blob. Database support for blobs is not universal.
Blobs were originally just big amorphous chunks of data invented by Jim Starkey at DEC, who describes them as "the thing that ate Cincinnati, Cleveland, or whatever" from "the 1958 Steve McQueen movie", referring to The Blob. Later, Terry McKiever, a marketing person for Apollo, felt that it needed to be an acronym and invented the backronym Basic Large Object. Then Informix invented an alternative backronym, Binary Large Object.
"Blobbing" originally meant moving large amounts of data from one database to another without filters or error correction. This is fast because it puts the responsibility for error checking and filtering on the new host for the data. The term arose from the image of somebody grabbing fistfuls of material from one container and putting it in another without regard to what was in the "blob" they were grasping.
The data type and definition was introduced to describe data not originally defined in traditional computer database systems, particularly because it was too large to store practically at the time the field of database systems was first being defined in the 1970s and 1980s. The data type became practical when disk space became cheap. This definition gained popularity with IBM's DB2.
Depending on the implementation and culture around usage, the concept might be alternately referred to as a "basic large object" or "binary data type". Also might be referred to as the acronym "BLOB".
- Starkey, James. "The true story of BLOBs". email. Retrieved 19 January 2006.
- "binary and varbinary (Transact-SQL)".
- "MySQL :: MySQL 5.0 Reference Manual :: 11.4.3 The BLOB and TEXT Types".
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