In Oracle we work with many types of datatypes. Some of the most popular datatypes are as follows:

Datatypes:-

CHAR : Values of this datatype are fixed length character strings of maximum length of 255 character. ORACLE7 compares CHAR using blank-padded comparison semantics.

VARCHAR/VARCHAR2 : Values of  this datatype are variable character strings of maximum length 2000.

Number : The Number datatype is used to store numbers (fixed of floating point). Numbers of virtually any magnitude may be stored up to 38 digits of precision. Numbers as large as 9.99 * 10 to the power of 124, i,e 1 followed by 125 zeros can be stored.

Date: The standard format is DD-MM-YY as in 18-OCT-1958. To enter dates other than the standard format use the appropriate functions. Data Time stores date in the 24-hours format. By default, the time in a date is 12:00:00 am, if no time portion is specified. The default date for a date field is the first day of the current month.

Long: Cells defined as LONG can store variable length characters strings containing upto 65,535  characters. Long date can be used to store arrays of binary data in ASCII format.