In Oracle 12c the maximum size of VARCHAR2, NVARCHAR2, and RAW has been increased to 32767 bytes from 4000 bytes for  VARCHAR2 and NVARCHAR2 and 2000 bytes for RAW. The init parameter MAX_STRING_SIZE must be set to the value of EXTENDED to use this increase size, if it is set to STANDARD, the old limits apply.  If VARCHAR2 and NVARCHAR2 are greater than 4000bytes and RAW greater than 2000bytes, they are considered EXTENDED data types and Oracle LOB technology is used for storage.  If tablespace is using Automatic Segment Space Management (ASSM), SecureFiles LOBs are used for storage, otherwise they use BasicFile LOBs.   The EXTENDED columns do not appear to be LOBs in the user operations and columns cannot be used with DBMS_LOB package.

Larry Catt

OCP