Chapter 3: Data Types and Subtypes

define columns in a database table in the CREATE TABLE statement or change columns using ALTER TABLE
declare or change a domain using the CREATE DOMAIN or ALTER DOMAIN statements
declare local variables in stored procedures, PSQL blocks and triggers and specify parameters in stored procedures
indirectly specify arguments and return values when declaring external functions (UDFs—user-defined functions)
provide arguments for the CAST() function when explicitly converting data from one type to another

Table 3.1. Overview of Data Types

Name	Size	Precision & Limits	Description
BIGINT	64 bits	From -2⁶³ to (2⁶³ - 1)	The data type is available in Dialect 3 only
BLOB	Varying	The size of a BLOB segment is limited to 64K. The maximum size of a BLOB field is 4 GB	A data type of a dynamically variable size for storing large amounts of data, such as images, text, digital sounds. The basic structural unit is a segment. The Blob subtype defines its content
CHAR(n), CHARACTER(n)	n characters. Size in bytes depends on the encoding, the number of bytes in a character	from 1 to 32,767 bytes	A fixed-length character data type. When its data is displayed, trailing spaces are added to the string up to the specified length. Trailing spaces are not stored in the database but are restored to match the defined length when the column is displayed on the client side. Network traffic is reduced by not sending spaces over the LAN. If the number of characters is not specified, 1 is used by default.
DATE	32 bits	From 01.01.0001 AD to 31.12.9999 AD	ISC_DATE. Date only, no time element
DECIMAL (`precision`, `scale`)	Varying (16, 32 or 64 bits)	`precision` = from 1 to 18, defines the least possible number of digits to store; `scale` = from 0 to 18, defines the number of digits after the decimal point	A number with a decimal point that has `scale` digits after the point. `scale` must be less than or equal to `precision`. Example: DECIMAL(10,3) contains a number in exactly the following format: ppppppp.sss
DOUBLE PRECISION	64 bits	2.225 * 10^-308 to 1.797 * 10³⁰⁸	Double-precision IEEE, ~15 digits, reliable size depends on the platform
FLOAT	32 bits	1.175 * 10^-38 to 3.402 * 10³⁸	Single-precision IEEE, ~7 digits
INTEGER, INT	32 bits	-2,147,483,648 up to 2,147,483,647	Signed long
NUMERIC (`precision`, `scale`)	Varying (16, 32 or 64 bits)	`precision` = from 1 to 18, defines the exact number of digits to store; `scale` = from 0 to 18, defines the number of digits after the decimal point	A number with a decimal point that has `scale` digits after the point. `scale` must be less than or equal to `precision`. Example: NUMERIC(10,3) contains a number in exactly the following format: ppppppp.sss
SMALLINT	16 bits	-32,768 to 32,767	Signed short (word)
TIME	32 bits	0:00 to 23:59:59.9999	ISC_TIME. Time of day. It cannot be used to store an interval of time
TIMESTAMP	64 bits (2 X 32 bits)	From start of day 01.01.0001 AD to end of day 31.12.9999 AD	Date and time of day
VARCHAR(n), CHAR VARYING, CHARACTER VARYING	n characters. Size in bytes depends on the encoding, the number of bytes in a character	from 1 to 32,765 bytes	Variable length string type. The total size of characters in bytes cannot be larger than (32KB-3), taking into account their encoding. The two trailing bytes store the declared length. There is no default size: the `n` argument is mandatory. Leading and trailing spaces are stored and they are not trimmed, except for those trailing characters that are past the declared length.

	Note About Dates
	Bear in mind that a time series consisting of dates in past centuries is processed without taking into account the actual historical facts, as though the Gregorian calendar were applicable throughout the entire series.