Question

I have a weird problem with a trigger in HSQLDB. I’ve checked the syntax several times but I haven’t found any mistakes. I now think that it may be impossible to create a subquery inside a trigger.

This is the code:

create trigger activate_member after update on member
        REFERENCING OLD AS old NEW AS new
        for each row
        begin atomic
                IF new.active = FALSE AND old.active = TRUE then
                        insert into member_inactive
                            (
                                member,
                                since,
                                until
                        )
                        values (
                                new.id,
                                (select since from member_active where
member = new.id AND since = (select max(since) from member_active where
member = new.id group by member)),
                                curdate()
                        );
                ELSEIF new.active = TRUE AND old.active = FALSE then
                        insert into member_active (member, since) values
(new.id, curdate());
                end if;
        end;

I think I’ve made everything correct: I have semicolons on every query inside the IF and ELSIEF statements, and trailing semicolon after end if.

But I still get this error message:

SEVERE  SQL Error at 'database.sql' line 125:
"create trigger activate_member after update on member
        REFERENCING OLD AS old NEW AS new
        for each row 
        begin atomic
                IF new.active = FALSE AND old.active = TRUE then
                        insert into member_inactive 
                        (
                                member, 
                                since, 
                                until
                        ) 
                        values (
                                new.id, 
                                (select since from member_active where member = new.id AND since = (select max(since) from member_active where member = new.id group by member)), 
                                curdate()
                        )"
unexpected end of statement:  required: ; : line: 17
org.hsqldb.cmdline.SqlTool$SqlToolException

But where I should add a semicolon? I think the problem is the subquery inside the insert, but that makes no sense.

Probably the begin atomic is problematic. But I see no other way to have an if-else statement inside a trigger without it!

Answer 1

i found now whats caused this problem: hsqldb only has begin atomic blocks inside a trigger.
Inside a begin atomic block i cannot use insert statements…

i now changed it to two triggers with where (statement) clauses, this works also