CLOB is similar to the oracle 7 long type, a clob can hold single-byte character data.
NCLOB stores fixed-width multibyte national character set data.
BLOB is similar to oracle & lon raw type, a BLOB can hold unstructred binary data.You can store and retrieve the data
BFIlEs allow read-only access to large binary files stored outside the oracle database.Unlike other three LOB types, BFile data is stored in a seperate file that is not maintained by oracle.Manipulations to BFILE data do not participate in oracle transactions.They can not be committed or rolled back.
store text as an image-use BLOB
store text- use CLOB