在 PostgreSQL 中创建触发器时出现语法错误

Question

I created a table name Student in PostgreSQL and then I tried defining a trigger on that table but it's showing an error message in doing so.

Trigger Syntax:

CREATE TRIGGER bi_Student BEFORE INSERT ON Student as $$ 
FOR EACH ROW
BEGIN
    raise notice 'Successfully inserted into table(%)', user;   
end $$;

Table Creation Command:

create table Student(Stu_id int, Stu_Name text, Stu_Age int, Stu_address char(30));

Actually I tried to declare the execution statements directly inside the trigger only rather than calling any procedure/ function from the trigger which is working fine but I want to do in this way in PostgreSQL.

Answer 1

PostgreSQL doesn't support it. You need trigger function always.

Answer 2

As documented in the manual you need atrigger function

create function my_trigger_function()
  returns trigger
as
$$
begin
  raise notice 'Successfully inserted into table(%)', user;   
  return new; --<< important (see the manual for details)
end
$$
language plpgsql;

Not sure what you intend with the user parameter there, as that is not the table name, but the current database user. If you want to display the actual table name, you need to use TG_RELNAME instead - which is an implicit variable available in the trigger function.

And a trigger definition

CREATE TRIGGER bi_Student 
BEFORE INSERT ON Student 
FOR EACH ROW
execute function my_trigger_function();