Data Model

Data Types

Supported	SQL Type Name	Alias	Size (byte)	Description	Range
O	boolean	bool	1		true/false
	bit		1		1/0
	varbit	bit varying
O	smallint	tinyint, int2	2	small-range integer value	-2^15 (-32,768) to 2^15 (32,767)
O	integer	int, int4	4	integer value	-2^31 (-2,147,483,648) to 2^31 - 1 (2,147,483,647)
O	bigint	bit varying	8	larger range integer value	-2^63 (-9,223,372,036,854,775,808) to 2^63-1 (9,223,372,036,854,775,807)
O	real	int8	4	variable-precision, inexact, real number value	-3.4028235E+38 to 3.4028235E+38 (6 decimal digits precision)
O	float[(n)]	float4	4 or 8	variable-precision, inexact, real number value
O	double	float8, double precision	8	variable-precision, inexact, real number value	1 .7E–308 to 1.7E+308 (15 decimal digits precision)
	number	decimal
	char[(n)]	character
	varchar[(n)]	character varying
O	text	text		variable-length unicode text
	binary	binary
	varbinary[(n)]	binary varying
O	blob	bytea		variable-length binary string
	date
	time
	timetz	time with time zone
	timestamp
	timestamptz
O	inet4		4	IPv4 address

Using real number value (real and double)

The real and double data types are mapped to float and double of java primitives respectively. Java primitives float and double follows the IEEE 754 specification. So, these types are correctly matched to SQL standard data types.

• float[( n )] is mapped to either float or double according to a given length n. If n is specified, it must be bewtween 1 and 53. The default value of n is 53.
• If 1 <- n <- 24, a value is mapped to float (6 decimal digits precision).
• If 25 <- n <- 53, a value is mapped to double (15 decimal digits precision).
• Do not use approximate real number columns in WHERE clause in order to compare some exact matches, especially the - and <> operators. The > or < comparisons work well.