What are the list of PL/SQL Scalar Data types ?

scalar datatypes are those which  hold a single value and do not have any internal components they are classified into below categories.

• The SQL data types
• BOOLEAN
• PLS_INTEGER
• BINARY_INTEGER
• REF CURSOR, explained in "Cursor Variables"
• User-defined subtypes

Oracle PL/SQL ;Data Types :Large Object (LOB) Datatypes

Large Object (LOB) Datatypes

Data Type Syntax	Oracle 9i	Oracle 10g	Oracle 11g	Explanation (if applicable)
bfile	Maximum file size of 4GB.	Maximum file size of 232-1 bytes.	Maximum file size of 264-1 bytes.	File locators that point to a binary file on the server file system (outside the database).
blob	Store up to 4GB of binary data.	Store up to (4 gigabytes -1) * (the value of the CHUNK parameter of LOB storage).	Store up to (4 gigabytes -1) * (the value of the CHUNK parameter of LOB storage).	Stores unstructured binary large objects.
clob	Store up to 4GB of character data.	Store up to (4 gigabytes -1) * (the value of the CHUNK parameter of LOB storage) of character data.	Store up to (4 gigabytes -1) * (the value of the CHUNK parameter of LOB storage) of character data.	Stores single-byte and multi-byte character data.
nclob	Store up to 4GB of character text data.	Store up to (4 gigabytes -1) * (the value of the CHUNK parameter of LOB storage) of character text data.	Store up to (4 gigabytes -1) * (the value of the CHUNK parameter of LOB storage) of character text data.	Stores unicode data.