The Oracle PL/SQL datatype MLSLABEL is used to store an operating system label in binary format. It is used for Oracle Label Security (which was earlier known as Trusted Oracle MLS RDBMS). The maximum precision for MLSLABEL column is 255 bytes; its Datatype Code is "105".
MLSLABEL s value is NULL in standard Oracle.
Note that Oracle has deprecated MLSLABEL but still supports it internally for backward compatibility.
SQL> CREATE TABLE T_MLS(A MLSLABEL);