Re: A transaction in transaction? Possible?

O Michael Fuhr έγραψε στις Nov 10, 2004 :

> On Wed, Nov 10, 2004 at 12:45:19AM -0800, Riccardo G. Facchini wrote:
>
> > Sorry, but I understand that your example is not really about nested
> > transactions, but about sequential transactions.
>
> Here's a more elaborate example. If this doesn't demonstrate the
> capability you're looking for, then please provide an example of
> what you'd like to do and describe the desired behavior.
>
> CREATE TABLE person (id SERIAL PRIMARY KEY, name TEXT NOT NULL);
>
> BEGIN;
> INSERT INTO person (name) VALUES ('Alice');
>
> SAVEPOINT s1;
> INSERT INTO person (name) VALUES ('Bob');
>
> SAVEPOINT s2;
> INSERT INTO person (name) VALUES ('Charles');
>
> SAVEPOINT s3;
> INSERT INTO person (name) VALUES ('David');
> ROLLBACK TO s3;
>
> INSERT INTO person (name) VALUES ('Edward');
> ROLLBACK TO s2;
>
> INSERT INTO person (name) VALUES ('Frank');
> RELEASE s1;
>
> INSERT INTO person (name) VALUES ('George');
> COMMIT;

Just a very naive thought....
Wouldn't make more sense to allow nested begin/commit/rollback blocks?

>
> SELECT * FROM person;
> id | name
> ----+--------
> 1 | Alice
> 2 | Bob
> 6 | Frank
> 7 | George
>
> If you change "ROLLBACK TO s2" to "RELEASE s2" then you get this:
>
> id | name
> ----+---------
> 1 | Alice
> 2 | Bob
> 3 | Charles
> 5 | Edward
> 6 | Frank
> 7 | George
>
> If you change "RELEASE s1" to "ROLLBACK TO s1" then you get this:
>
> id | name
> ----+--------
> 1 | Alice
> 7 | George
>
>

--
-Achilleus