systypes

All databases

Description

systypes contains one row for each system-supplied and user-defined datatype. Domains (defined by rules) and defaults are given, if they exist.

The rows that describe system-supplied datatypes cannot be altered.

Columns

The columns for systypes are:

Name	Datatype	Description
uid	int	User ID of datatype creator
usertype	smallint	User type ID
variable	bit	1 if datatype is variable length; 0 otherwise
allownulls	bit	Indicates whether nulls are allowed for this datatype
type	tinyint	Physical storage datatype
length	int	Physical length of datatype
tdefault	int	ID of system procedure that generates default for this datatype
domain	int	ID of system procedure that contains integrity checks for this datatype
name	sysname	Datatype name
printfmt	varchar(255)	Reserved
prec	tinyint	Number of significant digits
scale	tinyint	Number of digits to the right of the decimal point
ident	tinyint	1 if column has the IDENTITY property, 0 if it does not
hierarchy	tinyint	Precedence of the datatype in mixed mode arithmetic
accessrule	int	The object ID of the access rule in sysprocedures.
xtypeid	int	The internal class ID
xdbid	int	The dbid where a class is installed: -1 = the system database -2 = the current database

Table 1-28 lists each system-supplied datatype’s name, hierarchy, type (not necessarily unique), and usertype (unique). The datatypes are ordered by hierarchy. In mixed-mode arithmetic, the datatype with the lowest hierarchy takes precedence:

**Table 1-28: Datatype names, hierarchy, types, and usertypes**
Name	hierarchy	type	usertype
floatn	1	109	14
float	2	62	8
datetimn	3	111	15
datetime	4	61	12
real	5	59	23
numericn	6	108	28
numeric	7	63	10
decimaln	8	106	27
decimal	9	55	26
moneyn	10	110	17
money	11	60	11
smallmoney	12	122	21
smalldatetime	13	58	22
intn	14	38	13
int	15	56	7
smallint	16	52	6
tinyint	17	48	5
bit	18	50	16
univarchar	19	155	35
unichar	20	135	34
reserved	21
varchar	22	39	2
sysname	22	39	18
nvarchar	22	39	25
char	23	47	1
nchar	23	47	24
varbinary	24	37	4
timestamp	24	37	80
binary	25	45	3
text	26	35	19
image	27	34	20
date	28	123	37
time	29	124	38
daten	30	160	39
timen	31	29	40

Indexes

Unique clustered index On name

Unique nonclustered index On usertype