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8. 資料型別
Table 8.1 列出所有內建的通用資料型別。大多數列在「Aliases」中的替代名稱是由於在 PostgreSQL 內部使用的歷史因素。此外，還有一些內部使用或不建議使用的資料型別，但這裡並沒有列出。
Table 8.1. Data Types
Name | Aliases | Description |
|---|---|---|
bigint | int8 | signed eight-byte integer |
bigserial | serial8 | autoincrementing eight-byte integer |
bit [ (n) ] | | fixed-length bit string |
bit varying [ (n) ] | varbit | variable-length bit string |
boolean | bool | logical Boolean (true/false) |
box | | rectangular box on a plane |
bytea | | binary data (“byte array”) |
character [ (n) ] | char [ (n) ] | fixed-length character string |
character varying [ (n) ] | varchar [ (n) ] | variable-length character string |
cidr | | IPv4 or IPv6 network address |
circle | | circle on a plane |
date | | calendar date (year, month, day) |
double precision | float8 | double precision floating-point number (8 bytes) |
inet | | IPv4 or IPv6 host address |
integer | int,int4 | signed four-byte integer |
interval [fields] [ (p) ] | | time span |
json | | textual JSON data |
jsonb | | binary JSON data, decomposed |
line | | infinite line on a plane |
lseg | | line segment on a plane |
macaddr | | MAC (Media Access Control) address |
macaddr8 | | MAC (Media Access Control) address (EUI-64 format) |
money | | currency amount |
numeric [ (p,s) ] | decimal [ (p,s) ] | exact numeric of selectable precision |
path | | geometric path on a plane |
pg_lsn | | PostgreSQLLog Sequence Number |
point | | geometric point on a plane |
polygon | | closed geometric path on a plane |
real | float4 | single precision floating-point number (4 bytes) |
smallint | int2 | signed two-byte integer |
smallserial | serial2 | autoincrementing two-byte integer |
serial | serial4 | autoincrementing four-byte integer |
text | | variable-length character string |
time [ (p) ] [ without time zone ] | | time of day (no time zone) |
time [ (p) ] with time zone | timetz | time of day, including time zone |
timestamp [ (p) ] [ without time zone ] | | date and time (no time zone) |
timestamp [ (p) ] with time zone | timestamptz | date and time, including time zone |
tsquery | | text search query |
tsvector | | text search document |
txid_snapshot | | user-level transaction ID snapshot |
uuid | | universally unique identifier |
xml | | XML data |
以下資料型別（或其拼寫方式）是由 SQL 指定的：
bigint,bit,bit varying,boolean,char,character varying,character,varchar,date,double precision,integer,interval,numeric,decimal,real,smallint,time(with or without time zone),timestamp(with or without time zone),xml.每種資料型別都具有其明確的輸入和輸出功能外部表示法。許多內建的資料型別都有明顯的外部格式。但是，有幾種資料型別是 PostgreSQL 獨有的，比如幾何路徑，或者有幾種可能的格式，像是日期和時間型別。某些輸入和輸出功能是不可逆的，意即，與原始輸入相比，輸出功能的結果可能會失去一些精確度。