The built-in data types is twenty types but these divide in to six group in oracle :
- Character Datatypes      : CHAR, NCHAR, NVARCHAR2, VARCHAR2
- Number Datatypes        : NUMBER, BINARY_FLOAT, BINARY_DOUBLE
- Datetime Datatypes       : DATE, TIMESTAMP, INTERVAL YEAR TO MONTH, INTERVAL DAY TO SECOND
- Row ID Datatypes         : ROWID, UROWID
- Long and Row Datatypes  : LONG, LONG RAW, RAW
- Large Object Datatypes    : BLOB, CLOB, NCLOB, BFILE