18.104.22.168.3 Partially Length-Prefixed Data Types
The data value corresponding to the set of data types defined in this section follows the rule defined in the partially length-prefixed stream definition (section 22.214.171.124.3).
PARTLENTYPE = XMLTYPE / BIGVARCHARTYPE / BIGVARBINARYTYPE / NVARCHARTYPE / UDTTYPE
BIGVARCHARTYPE, BIGVARBINARYTYPE, and NVARCHARTYPE can represent two types each:
The regular type with a known maximum size range from 0 to 8000, defined by USHORTLEN_TYPE.
A type with unlimited max size, known as varchar(max), varbinary(max) and nvarchar(max), which has a max size of 0xFFFF, defined by PARTLENTYPE. This class of types was introduced in TDS 7.2.