This type of field can keep values in the range 0..16777215.
This field always uses 3 bytes on disk per value.
This field can be declared as Nullable. In this case a special bitmap is associated with this field.
This field can have flag fIndexed.
This field can have flag fUnique.
This field type is represented at the API level by VUMedium Class.
At SQL Level you can create such field using
CREATE TABLE T1( fldUMedium UMEDIUM );
You can use this field in any predicate expression, e.g.
SELECT * FROM T1 WHERE fldUMedium = 54;