Oracle Data Types

Character Data-types:

Data Type	Explanation
char(size)	size is the number of characters to store. Fixed-length strings. Space padded.
nchar(size)	size is the number of characters to store. Fixed-length NLS string Space padded.
nvarchar2(size)	size is the number of characters to store. Variable-length NLS string.
varchar2(size)	size is the number of characters to store. Variable-length string.
long	Variable-length strings. (backward compatible)
raw	Variable-length binary strings
long raw	Variable-length binary strings. (backward compatible)

Numeric Data-types

Data Type	Explanation
number(p,s)	p is the precision and s is the scale. For example, number(8,2) is a number that has 6 digits before the decimal and 2 digits after the decimal.
numeric(p,s)	p is the precision and s is the scale. For example, numeric(8,2) is a number that has 6 digits before the decimal and 2 digits after the decimal.
float
dec(p,s)	p is the precision and s is the scale. For example, dec(5,1) is a number that has 4 digits before the decimal and 1 digit after the decimal.
decimal(p,s)	p is the precision and s is the scale. For example, decimal(5,1) is a number that has 4 digits before the decimal and 1 digit after the decimal.
integer
int
smallint
real
double precision

Date/Time:

Data Type	Explanation
date
timestamp (fractional seconds precision)	Includes year, month, day, hour, minute, and seconds. For example: timestamp(6)
timestamp (fractional seconds precision) with time zone	Includes year, month, day, hour, minute, and seconds; with a time zone displacement value. For example: timestamp(5) with time zone
timestamp (fractional seconds precision) with local time zone	Includes year, month, day, hour, minute, and seconds; with a time zone expressed as the session time zone. For example: timestamp(4) with local time zone
interval year (year precision) to month	Time period stored in years and months. For example: interval year(4) to month
interval day (day precision) to second (fractional seconds precision)	Time period stored in days, hours, minutes, and seconds. For example: interval day(2) to second(6)

Large Object (LOB):

Data Type	Explanation
bfile	File locators that point to a binary file on the server file system (outside the database).
blob	Stores unstructured binary large objects.
clob	Stores single-byte and multi-byte character data.
nclob	Stores unicode data.

Rowid Data-types

Data Type	Explanation
rowid	Fixed-length binary data. Every record in the database has a physical address or rowid.
urowid(size)	Universal rowid. size is optional.