Binary Large Object (BLOB)

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A Binary Large Object (BLOB) represents a collection of binary data that is treated as a single information value.

BLOBs are commonly used when the internal content is not naturally represented as ordinary textual, numeric, or relational data. The consumer of the BLOB interprets the binary content according to information associated with the value, such as its media type, format, schema, encoding, or other contextual metadata.

BLOB content may represent information such as:

• images
• audio
• video
• documents
• archives
• executable artifacts
• encoded or serialized objects
• cryptographic material
• compressed information
• proprietary binary formats
• other arbitrary binary content

A BLOB is treated as a single opaque value rather than as a structure whose internal elements are interpreted by the containing information model.

The containing model may store, transmit, reference, associate, or otherwise manage the BLOB without understanding the internal organization of its binary content.

Any internal organization of the binary content is determined by the applicable format, schema, encoding, media type, codec, or consuming implementation.

The term “large” does not establish a specific minimum or maximum size. It distinguishes the concept from ordinary scalar values and reflects the historical use of BLOBs for potentially substantial binary content.

a collection of binary data treated as a single information value

A BLOB defines the semantic treatment of binary content as a single information value.

The BLOB concept does not prescribe or expose internal semantic boundaries, named fields, records, or other structured subelements within the binary content. The containing information model treats the value as opaque.

Although binary content is physically represented using units such as bits and bytes, those physical representation boundaries do not constitute semantic structure imposed by the BLOB concept.

Any internal organization of the binary content is determined by the applicable format, schema, encoding, media type, codec, or consuming implementation, not by the BLOB concept itself.

A BLOB does not prescribe a storage datatype, serialization, compression method, encryption method, transport representation, or maximum size.

Logical and platform-specific mappings may represent a BLOB differently while preserving its conceptual semantics.

The binary contents of an image file may be represented as a BLOB while separate attributes identify the image format, filename, media type, or other descriptive information.