Oracle Database VARCHAR2 CLOB transfer error:
ALTER TABLE TABLE_NAME
MODIFY ( "FIELD" CLOB ) ;
ORA-22858: oracle not allow certain types of field modification.
The field type is not specifically modified to:
Object, the REF, nested Table, VARRAYs, the CLOB, the BLOB
solutions to rebuild the table, with clob field;
New clob field replacement.
Reproduced in: https: //www.cnblogs.com/JavaHh/p/11023737.html