Hsqldb 简明教程
HSQLDB - Data Types
此章节解释了 HSQLDB 的不同数据类型。HSQLDB 服务器提供了六类数据类型。
This chapter explains the different datatypes of HSQLDB. HSQLDB server offers six categories of data types.
Exact Numeric Data Types
Data Type |
From |
To |
bigint |
-9,223,372,036,854,775,808 |
9,223,372,036,854,775,807 |
int |
-2,147,483,648 |
2,147,483,647 |
smallint |
-32,768 |
32,767 |
tinyint |
0 |
255 |
bit |
0 |
1 |
decimal |
-10^38 +1 |
10^38 -1 |
numeric |
-10^38 +1 |
10^38 -1 |
money |
-922,337,203,685,477.5808 |
+922,337,203,685,477.5807 |
smallmoney |
-214,748.3648 |
+214,748.3647 |
Approximate Numeric Data Types
Data Type |
From |
To |
float |
-1.79E + 308 |
1.79E + 308 |
real |
-3.40E + 38 |
3.40E + 38 |
Date and Time Data Types
Data Type |
From |
To |
datetime |
Jan 1, 1753 |
Dec 31, 9999 |
smalldatetime |
Jan 1, 1900 |
Jun 6, 2079 |
date |
Stores a date like June 30, 1991 |
time |
Note - 此处，datetime 的精度为 3.33 毫秒，而 small datetime 的精度为 1 分钟。
Note − Here, datetime has 3.33 milliseconds accuracy whereas small datetime has 1- minute accuracy.
Character Strings Data Types
Data Type |
Description |
char |
Maximum length of 8,000 characters (Fixed length non-Unicode characters) |
varchar |
Maximum of 8,000 characters (Variable-length non-Unicode data) |
varchar(max) |
Maximum length of 231 characters, variable-length non-Unicode data (SQL Server 2005 only) |
text |
Variable-length non-Unicode data with a maximum length of 2,147,483,647 characters |
Unicode Character Strings Data Types
Data Type |
Description |
nchar |
Maximum length of 4,000 characters (Fixed length Unicode) |
nvarchar |
Maximum length of 4,000 characters (Variable length Unicode) |
nvarchar(max) |
Maximum length of 231 characters (SQL Server 2005 only),(Variable length Unicode) |
ntext |
Maximum length of 1,073,741,823 characters (Variable length Unicode) |
Binary Data Types
Data Type |
Description |
binary |
Maximum length of 8,000 bytes (Fixed length binary data) |
varbinary |
Maximum length of 8,000 bytes (Variable length binary data) |
varbinary(max) |
Maximum length of 231 bytes (SQL Server 2005 only), (Variable length Binary data) |
image |
Maximum length of 2,147,483,647 bytes (Variable length Binary Data) |
Misc Data Types
Data Type |
Description |
sql_variant |
Stores values of various SQL Server-supported data types, except text, ntext, and timestamp |
timestamp |
Stores a database-wide unique number that gets updated every time a row gets updated |
uniqueidentifier |
Stores a globally unique identifier (GUID) |
xml |
Stores XML data. You can store xml instances in a column or a variable (SQL Server 2005 only) |
cursor |
Reference to a cursor object |
table |
Stores a result set for later processing |