小编Apo*_*dis的帖子

我在 PostgreSQL 中创建了这个 PL/pgSQL 触发器函数：

CREATE or replace FUNCTION public.trigger31()
        RETURNS trigger
        LANGUAGE 'plpgsql'
        COST 100
        VOLATILE NOT LEAKPROOF 
    AS $BODY$
    begin
        if(TG_OP='INSERT') then
            if(New.start_date>(select max(end_date) from "Semester") and New.end_date>New.start_date) then

                Insert Into "Semester" (semester_id,academic_year,academic_season,start_date,end_date,semester_status)
                values (New.semester_id=(select max(s.semester_id)+1 from "Semester" s):: integer,
                        new.academic_year= academic_year_trig(),
                        new.academic_season=academic_season_trig(),
                        new.start_date,new.end_date,
                        new.semester_status=semester_stat_trig()
                    );
                return NEW;
            else
                RAISE EXCEPTION 'Invalid start_date or end_date';
            end if;
        end if;
    end;
$BODY$;

尝试执行它，我收到此错误：

ERROR:  column "semester_id" is of type integer but expression is of type boolean
LINE 2:    values …

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在 Fiware 教程中，我读到 NGSI-LD 不是 100% JSON-LD。你能解释一下有哪些区别吗？