BLOB data columns cannot be part of an index.

BLOB data columns cannot be used for variables or as parameters in stored procedures.

Comparison operations are not supported on BLOB columns. Comparison operations between BLOB columns are not supported. Comparison operations between BLOB columns and columns of other data types are not supported.

Conversion, aggregate, and scalar functions are disallowed on this data type.

BLOB does not have National Language Support (NLS).

The default size for a BLOB is 32000 bytes.