All databases
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.
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:
|
Table 12-26 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:
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 |
