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