PostgreSQL 生成列

PostgreSQL 生成列的三种使用方式

自定义函数

CREATE OR REPLACE FUNCTION public.f2 (name text)
    RETURNS text
    LANGUAGE plpgsql
    IMMUTABLE
    AS $function$
BEGIN
    RETURN substring($1, 1, 10);
END;
$function$ 

CREATE TABLE people_gc_stored (
    name text,
    small_name text GENERATED ALWAYS AS (f2 (name)) STORED
);

GENERATED ALWAYS

CREATE TABLE people_gc_stored1 (
    name text,
    small_name text GENERATED ALWAYS AS IDENTITY
);

GENERATED DEFAULT

CREATE TABLE people_gc_stored2 (
    name text,
    small_name text GENERATED DEFAULT AS IDENTITY
);