Values:
TYPE_UNSPECIFIED (0):
Unspecified name mapping type.
DATABASE (1):
The object being mapped is a database.
SCHEMA (2):
The object being mapped is a schema.
RELATION (3):
The object being mapped is a relation.
ATTRIBUTE (4):
The object being mapped is an attribute.
RELATION_ALIAS (5):
The object being mapped is a relation alias.
ATTRIBUTE_ALIAS (6):
The object being mapped is a an attribute
alias.
FUNCTION (7):
The object being mapped is a function.