Contains a row for each system and user-defined type.
|Column name||Data type||Description|
|name||sysname||Name of the type. Is unique within the schema.|
|system_type_id||tinyint||ID of the internal system type.|
|user_type_id||int||ID of the type. Is unique within the database. For system data types, user_type_id = system_type_id.
CLR assembly types such as hierarchyid, geometry and geography, will have a different system_type_id, and can be identified using is_assembly_type. The sysname data type is an internal data type based on nvarchar.
|schema_id||int||ID of the schema to which the type belongs.|
|principal_id||int||ID of the individual owner if different from schema owner. By default, schema-contained objects are owned by the schema owner. However, an alternate owner can be specified by using the ALTER AUTHORIZATION statement to change ownership.
NULL if there is no alternate individual owner.
|max_length||smallint||Maximum length (in bytes) of the type.
-1 = Column data type is varchar(max), nvarchar(max), varbinary(max), or xml.
For text columns, the max_length value will be 16.
|precision||tinyint||Max precision of the type if it is numeric-based; otherwise, 0.|
|scale||tinyint||Max scale of the type if it is numeric-based; otherwise, 0.|
|collation_name||sysname||Name of the collation of the type if it is character-based; other wise, NULL.|
|is_nullable||bit||Type is nullable.|
|is_user_defined||bit||1 = User-defined type.
0 = SQL Server system data type.
|is_assembly_type||bit||1 = Implementation of the type is defined in a CLR assembly.
0 = Type is based on a SQL Server system data type.
|default_object_id||int||ID of the stand-alone default that is bound to the type by using sp_bindefault.
0 = No default exists.
|rule_object_id||int||ID of the stand-alone rule that is bound to the type by using sp_bindrule.
0 = No rule exists.
|is_table_type||bit||Indicates the type is a table.|
The visibility of the metadata in catalog views is limited to securables that a user either owns or on which the user has been granted some permission. For more information, see Metadata Visibility Configuration.