Postgresql - Data types 数据类型

PG有着最丰富的数据类型。我们看一下都有那种。摘自官网。

https://www.postgresql.org/docs/10/static/datatype.html

 

1. Numeric

Name	Storage Size	Description	Range
smallint	2 bytes	small-range integer	-32768 to +32767
integer	4 bytes	typical choice for integer	-2147483648 to +2147483647
bigint	8 bytes	large-range integer	-9223372036854775808 to +9223372036854775807
decimal	variable	user-specified precision, exact	up to 131072 digits before the decimal point; up to 16383 digits after the decimal point
numeric	variable	user-specified precision, exact	up to 131072 digits before the decimal point; up to 16383 digits after the decimal point
real	4 bytes	variable-precision, inexact	6 decimal digits precision
double precision	8 bytes	variable-precision, inexact	15 decimal digits precision
smallserial	2 bytes	small autoincrementing integer	1 to 32767
serial	4 bytes	autoincrementing integer	1 to 2147483647
bigserial	8 bytes	large autoincrementing integer	1 to 9223372036854775807

 

2. Monetary

Name	Storage Size	Description	Range
money	8 bytes	currency amount	-92233720368547758.08 to +92233720368547758.07

 

3. Character

Name	Description
character varying(n), varchar(n)	variable-length with limit
character(n), char(n)	fixed-length, blank padded
text	variable unlimited length

 

4. Binary Data

Name	Storage Size	Description
bytea	1 or 4 bytes plus the actual binary string	variable-length binary string

 

5. Date/Time

Name	Storage Size	Description	Low Value	High Value	Resolution
timestamp [ (p) ] [ without time zone ]	8 bytes	both date and time (no time zone)	4713 BC	294276 AD	1 microsecond
timestamp [ (p) ] with time zone	8 bytes	both date and time, with time zone	4713 BC	294276 AD	1 microsecond
date	4 bytes	date (no time of day)	4713 BC	5874897 AD	1 day
time [ (p) ] [ without time zone ]	8 bytes	time of day (no date)	00:00:00	24:00:00	1 microsecond
time [ (p) ] with time zone	12 bytes	time of day (no date), with time zone	00:00:00+1459	24:00:00-1459	1 microsecond
interval [ fields ] [ (p) ]	16 bytes	time interval	-178000000 years	178000000 years	1 microsecond

 

6. Boolean

Name	Storage Size	Description
boolean	1 byte	state of true or false

 

7. Enumerated

Enumerated (enum) types are data types that comprise a static, ordered set of values. They are equivalent to the enum types supported in a number of programming languages. An example of an enum type might be the days of the week, or a set of status values for a piece of data.

Example: create type mood as enum('sad', 'ok', 'happy');

 

8. Geometric

Name	Storage Size	Description	Representation
point	16 bytes	Point on a plane	(x,y)
line	32 bytes	Infinite line	{A,B,C}
lseg	32 bytes	Finite line segment	((x1,y1),(x2,y2))
box	32 bytes	Rectangular box	((x1,y1),(x2,y2))
path	16+16n bytes	Closed path (similar to polygon)	((x1,y1),...)
path	16+16n bytes	Open path	[(x1,y1),...]
polygon	40+16n bytes	Polygon (similar to closed path)	((x1,y1),...)
circle	24 bytes	Circle	<(x,y),r> (center point and radius)

 

9. Network Address

Name	Storage Size	Description
cidr	7 or 19 bytes	IPv4 and IPv6 networks
inet	7 or 19 bytes	IPv4 and IPv6 hosts and networks
macaddr	6 bytes	MAC addresses
macaddr8	8 bytes	MAC addresses (EUI-64 format)

 

10. Bit String

Bit String是1和0的字符串，用来存储或可视化bit掩码。有两种SQL位类型：bit(n) 和bit (n)，其中n是正整数。

bit类型数据必须精确匹配长度n；试图存储较短或更长的位串是错误的。可变长度的bit数据的可变到最大长度n；较长的字符串将被拒绝。没有长度的写入位相当于位（1），而没有长度规格的位变化意味着无限长。

Example: INSERT INTO test VALUES (B'10'::bit(3), B'101');

 

11. Text Search

PostgreSQL提供了两种数据类型，它们被设计为支持全文搜索，这是通过自然语言文档集合搜索以找到与查询最匹配的那些活动。tsvector类型表示以文本搜索优化的形式的文档；tsquery类型同样表示文本查询。

tsvector存储不同的词的排序列表，这些词被归一化以合并同一单词的不同变体。排序和重复消除是在输入过程中自动完成的，

mytest=# select ' '' '' a b c d a d c b e'::tsvector;

tsvector

-------------------------

' ' 'a' 'b' 'c' 'd' 'e'

(1 row)

tsquery存储要搜索的次，使用布尔运算符&， |， ！和组合它们以及短语搜索操作符<>。

mytest=# select 'a & b &! c'::tsquery;

tsquery

------------------

'a' & 'b' & !'c'

(1 row)

 

12. UUID

存储Universally Unique Identifiers (UUID)。该标识符是由选择的算法生成的128位相同的标识符不太可能由已知的宇宙中的任何其他人使用相同的算法生成。

对于分布式系统，这些标识符提供了比序列生成器更好的唯一性保证，这些序列生成器在单个数据库中是唯一的。

UUID被写为一个小写的十六进制数字序列，在几个由连字符分开的组中，具体地是一组8位数字，后面是三组4位数字，后面是一组12位数字，总共代表128位的32位数字。

例如：a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11

 

13. XML

存储XML数据。

它在文本字段中存储XML数据的优点在于，它检查输入值的正确性，并且有支持函数对其执行类型安全操作。

使用此数据类型需要安装的时候配置 --with-libxml。

可以存储由XML标准定义的格式良好的“文档”，以及由XML定义的“内容”片段。XML标准中的内容。粗略地说，这意味着内容片段可以有不止一个顶层元素或字符节点。XMLValk为文档的表达式可用于评估特定的XML值是否为完整文档或仅为内容片段。

 

14. JSON

存储JSON (JavaScript Object Notation)。

JSON包括: json and jsonb.

 

15. Arrays

 

16. Composite

 

17. Range

 

18. Object Identifier

 

19. pg_lsn

存储 LSN (Log Sequence Number)数据， 64-bit 的数字。存储的是WAL的位置点。

 

20. Pseudo-Types

Name	Description
any	Indicates that a function accepts any input data type.
anyelement	Indicates that a function accepts any data type.
anyarray	Indicates that a function accepts any array data type.
anynonarray	Indicates that a function accepts any non-array data type.
anyenum	Indicates that a function accepts any enum data type.
anyrange	Indicates that a function accepts any range data type.
cstring	Indicates that a function accepts or returns a null-terminated C string.
internal	Indicates that a function accepts or returns a server-internal data type.
language_handler	A procedural language call handler is declared to return language_handler.
fdw_handler	A foreign-data wrapper handler is declared to return fdw_handler.
index_am_handler	An index access method handler is declared to return index_am_handler.
tsm_handler	A tablesample method handler is declared to return tsm_handler.
record	Identifies a function taking or returning an unspecified row type.
trigger	A trigger function is declared to return trigger.
event_trigger	An event trigger function is declared to return event_trigger.
pg_ddl_command	Identifies a representation of DDL commands that is available to event triggers.
void	Indicates that a function returns no value.
unknown	Identifies a not-yet-resolved type, e.g. of an undecorated string literal.
opaque	An obsolete type name that formerly served many of the above purposes.