CREATE TYPE new_data_type AS ENUM ('value1', 'value2', 'value3'); 复制代码 这将创建一个名为new_data_type的新数据类型,它具有三个可能的值:value1,value2和value3。 创建一个使用新数据类型的表: CREATE TABLE example_table ( id SERIAL PRIMARY KEY, name new_data_type ); 复制代码 这将...
typedef union { struct /* Normal varlena (4-byte length) */ { uint32 va_header; char va_data[FLEXIBLE_ARRAY_MEMBER]; } va_4byte; struct /* Compressed-in-line format */ { uint32 va_header; /*头部存放了压缩后的长度*/ uint32 va_tcinfo; /* Original data size (excludes header) an...
Values can be added anywhere in between as enums have a sort order which is the order in which the value was inserted, and it is preserved. ALTER TYPE e_contact_method ADD VALUE 'Twitter' BEFORE 'Sms'; # select t.typname, e.enumlabel, e.enumsortorder from pg_type t, pg_enum e ...
在本练习中,您将创建一个名为compass_position的新ENUM数据类型。 -- Create an enumerated data type, compass_positionCREATETYPEcompass_positionASENUM(-- Use the four cardinal directions'North','South','East','West');-- Confirm the new data type is in the pg_type system tableSELECTtypname,typc...
枚举类型(enum) 约束 主键primary key:物理上存储的顺序 非空not null:此字段不允许填写空值 惟一unique:此字段的值不允许重复 默认default:当不填写此值时会使用默认值,如果填写时以填写为准 外键foreign key:对关系字段进行约束,当为关系字段填写值时,会到关联的表中查询此值是否存在,如果存在则填写成功,如果不...
Enums in Postgres are a custom data type. They allow you to define a set of values (or labels) that a column can hold. They are useful when you have a fixed set of possible values for a column.Creating enums#You can define a Postgres Enum using the create type statement. Here's ...
*/typedefenumForkNumber{InvalidForkNumber=-1,MAIN_FORKNUM=0,FSM_FORKNUM,VISIBILITYMAP_FORKNUM,INIT_FORKNUM,/* * NOTE: if you add a new fork, change MAX_FORKNUM and possibly * FORKNAMECHARS below, and update the forkNames array in ...
enum Type { RECORD = 0; TAG = 1; } // 记录的具体内容 message RecordData { string content = 1; repeated string images = 2; } // 标签的具体内容 message TagData { string title = 1; } // 资源ID int32 id = 2; // 资源类型 ...
如果要修改类型枚举表,可以使用ALTER TYPE命令。以下示例将修改名为"status"的类型枚举表,将其中的一个枚举值"old_value"修改为"new_value": 注意,此命令只能修改一个枚举值的名称。如果需要添加、删除或重新排序多个枚举值,需要使用其他方法。 如果要添加类型枚举值,可以使用CREATE TYPE命令和ENUM关键字。以下示例将...
Issue type: bug report Database system/driver: postgres TypeORM version: 0.2.6 as reported by $ typeorm version Local installed version: 0.2.6 Global installed TypeORM version: 0.2.6 Steps to reproduce or a small repository showing the problem: The cause seems to be this entity: enum State...