Adriano dos Santos Fernandes wrote:

> Vlad Khorsun wrote:
>
>> c) Syntax rule 3 means truncated table must not participate in FOREIGN KEY constraints as
>> master table.
>> ORACLE relaxed this rule and allow self-referenced constraints. I think we can follow it.
>>
>>
> Can't we also allow it when all detail tables are being truncated on the
> same transaction?
>
>
>

There are serious problems making TRUNCATE transactional. For example,
what happens when a transaction does TRUNCATE then an insert into the
table, then rolls back. It can be handled -- anything can with enough
effort, resource, and time -- but is it feasible? Database systems
built around logs can be made to handle this, but Firebird doesn't have
a log.

Savepoints make things even worse. Imagine having to undo a TRUNCATE in
nested savepoints.

How do you recommend that Firebird handle the following:

insert
truncate
insert
truncate
insert
truncate
rollback

The SQL committee not-with-standing, almost every serious designer
having contemplated the runtime and permission problems has decided that
TRUNCATE is a DDL, not DML, operation.