II. Foundation of SQL

1. Introduction to Oracle Common database types

The data types available in oracle11g are 23, but we use common data types that are typically within 10 of the day. The following table describes the common data types:

Oracle Common data Types list

Type	Data type	Value range (bytes)	Description
Word Character Type	Varchar2	0-4000	Variable-length strings (most commonly used)
	Nvarchar2	0-1000	Variable-length character data for storing Unicode character sets
	Char	0-2000	Character data for describing fixed-length
	NChar	0-1000	Character data for storing fixed-length Unicode character sets
	Long	0-2gb	Used to store variable-length strings (rarely used)
Digital type	Number (P,s)	P Maximum accuracy is 38 bits (decimal)	P: precision; s: decimal places can store fixed-length integers and decimals
	Float	Store 126-bit data (binary)	The storage accuracy is calculated in binary, multiplied by 0.30103 when converted to decimal
Date type	Date	Used to store date and time ranges BC 4712-01-01 to 9999-12-31
	Timestamp	It is more accurate than date, date is accurate to seconds, and timestamp to fractional seconds, in addition to showing morning, afternoon
Other types	Blob	0-4gb	Storing binary data
	Clob	0-4gb	Storing string data
	bfile	Size is related to the operating system	Used to store unstructured binary data in operating system files other than the database