char=char(1)。 text:不限长。最长的可能字符串大概是1GB左右。 在postgresql中的char(n)通常在三个当中最慢的,因为需要读取空白字符的额外开销。一般应该使用varchar或text 7.bytea hex format:将二进制数据编码为每字节两位十六进制数据,整条字符串以\x开头。这种模式能够和很多外部应用程序和协议兼容,转换比“...
PostgreSQL Text Data Type 1) PostgreSQL Char Data Type Character data, often known as CHAR in PostgreSQL, represent the character type values. In other words, the PostgreSQL character data type is used when you want the variable to store a character of limited length. This length value can be...
SQL指定之外的通用数据类型为:bigserial,box,bytea,cidr,circle,inet,json,jsonb,line,lseg,macaddr,macaddr8,money,path,pg_lsn,pg_snapshot,point,polygon,smallserial,serial,text,tsquery,tsvector,txid_snapshot,uuid。 AI检测代码解析 GenericType: type_function_name opt_type_modifiers { $$ = makeTypeN...
These Data Type stores store IPv4, IPv6, and MAC addresses. Category - Bit String Type Bit String Types are used to store bit masks. They are either 0 or 1. There are two bit types - bit(n) and bit varying(n), where n is a positive integer. Category - Text Search Type Used for...
Luckily, we have a couple of possibilities for managing the TEXT data type for a PostgreSQL database: We can use the@Lobannotation Alternatively, we can also use the@Columnannotation, combined with thecolumnDefinitionattribute Let’s now take a look at the two solutions beginning with the@Loban...
发现text类型中的abc和def在数据文件表示为 09616263和09646566,查看代码可知text类型其实为varlena,他的结构为: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 struct varlena { char vl_len_[4]; /* Do not touch this field directly! */ char vl_dat[1]; }; 前四个字节为长度标识,在这里只有一...
Column | Type | Modifiers ---+---+--- col | text | col_asc | integer | col_desc | integer | col_rand | integer | data | text | Indexes: "tbl_corr_asc_idx" btree (col_asc) "tbl_corr_desc_idx" btree (col_desc) "tbl_corr_rand_idx" btree (col...
tsquery text search query tsvector text search document txid_snapshot user-level transaction id snapshot uniqueidentifier uuid universally unique identifier:唯一标识类型 xml xml xml xml data:xml数据类型 json json data 21 21 39 15 39分类...
text 可变长度字符串。 3.日期/时间数据类型 名称 描述 存储大小 最小值 最大值 timestamp [ (p) ] [不带时区 ] 日期和时间(无时区) 8字节 4713 bc 294276 ad timestamp [ (p) ]带时区 包括日期和时间,带时区 8字节 4713 bc 294276 ad date 日期(没有时间) 4字节 4713 bc 5874897 ad time [ ...
make_timestamptz(year int, month int, day int, hour int, min int, sec double precision, [ timezone text ])函数通过指定年、月、日、时、分、秒创建一个带时区的时间戳。如果没有指定时区,使用当前时区。 SELECTmake_timestamptz(2020,3,15,8,20,23.5);make_timestamptz|---|2020-03-1508:20...