PostgreSQL has a rich set of native data types available to users. Users can add new types to PostgreSQL using the CREATE TYPE command. PostgreSQL有一组丰富的本地数据类型可供用户使用。用户可以使用CREATE TYPE命令向PostgreSQL添加新类型。Each data type has an external representation determined by its...
In this tutorial, you will learn about PostgreSQL BYTEA data type and how to use it to store binary strings in the database.
在许多编程语言支持枚举类型,它们是相等。 Unlike other types, Enumerated Types need to be created using CREATE TYPE command. This type is used to store a static, ordered set of values, for example compass directions, i.e. NORTH, SOUTH, EAST, and WEST or days of the week as below: CREATE...
The bytea data type allows storage of binary strings bytea 类型 允许存储二进制串 A binary string is a sequence of octets (or bytes) 这里的binary string 是一串 octets ,也就是存储最小单位是 octet. 备注: octets 和 byte 的区别 最近项目中写文档,由于跟老外合作,所有都是英文的。经常遇到octet这...
bytea_output = 'escape' # hex, escape 意思是设置bytea_output的输出类型设置为转义类型输出,而postgres默认是hex类型输出,所以导致转换数据混乱问题 参考文档: 8.4. Binary Data Types The bytea data type allows storage of binary strings; see Table 8-6. ...
1、PLpgSQL_datum.dtype共有5中类型,其中2中类型属于通用类型,覆盖pg_type中所有类型:由plpgsql_build_variable函数根据pg_type中查到的类型决定(对应关系见下表中的PLPGSQL_DTYPE_VAR、PLPGSQL_DTYPE_REC)
实际上bytea多个十六进制值使用E’\xFC’ 类似于Oracle中的rawtohex函数。只不过Oracle中的rawtohex函数转换后的值为大写十六进制字符串。实际上如果要在上表中的col2中插入E’\xFG’时,会提示G不是一个有效的十六进制字符。 同时需要注意的是,如果使用E’\xF’只包含单个十六进制字符时,使用一个反斜杠,如果有多...
BackendKeyData (B) Byte1('K') :标志报文为取消关键数据,前端必须保存这些值,以便用于之后的CancelRequest报文 Int32(12) :内容长度,包含自身 Int32 :后端processID Int32 :后端的密钥 Bind (F) Byte1('B') :标志报文为Bind命令 Int32 :内容长度,包含自身 String :目标portal的名字(空字符串表示未命名)...
{uint16 n_header;/* Header word */struct NumericLong n_long;/* Long form (4-byte header) */struct NumericShort n_short;/* Short form (2-byte header) */};struct NumericData{int32 vl_len_;/* varlena header (do not touch directly!) */union NumericChoice choice;/* choice of ...
Character Types Date/Time Types Boolean Type Enumerated Type 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. Unlike other types, Enumerated Types need to be created using ...