Re: [Mged-mage] MAGE-stk help needed

[Mohammad s. <sh...@eb...>]

Hi Angel,

This  mysql Gotchas page seems either not up-to-date with the latest 
MySQL or wrong to me!
for instance in the discussion about AUTO_INCREMENT;
first of all MySQL amnual explicitely says:

"Note that if the user specifies NULL or 0 for the AUTO_INCREMENT column 
in an INSERT, InnoDB treats the row as if the value had not been 
specified and generates a new value for it."

yet you see in mysql Gotchas page that writer has played around 
inserting 0 into autoincrement field, I mean why on earth would you want 
to put a 0 in the auto_increment field ? and yet the result is not what 
you get when you try it:

This is exactly from the Gotchas page:

<<<<

The previous gotcha leads us to this interesting problem, which is 
possibly the proof that 1 equals 2:

CREATE TABLE exmpl3 (
  id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  val TEXT
) type=innodb;

INSERT INTO exmpl3 VALUES(0, 'test');
INSERT INTO exmpl3 VALUES(1, 'test');
mysql> select * from exmpl3;
+----+------+
| id | val  |
+----+------+
|  1 | test |
|  2 | test |
+----+------+
2 rows in set (0.00 sec)

Isn't this fun? Now let's get ambitious:

 >>>>


BUT ITS NOT TRUE!

after inserting the first statement MySQL turn 0 to 1 and insert 
(1,'test') into the table (As it explicitely mentioned in the MySQL 
Manual) and by trying the second insert statement this is what you get:

INSERT INTO exmpl3 VALUES(1, 'test');
ERROR 1062: Duplicate entry '1' for key 1

and you never see such a result

+----+------+
| id | val  |
+----+------+
|  1 | test |
|  2 | test |
+----+------+


2 rows in set (0.00 sec)

:
This is exactly like not using SEQUENCE object in Oracle or PostgreSQL 
and inserting an existing Primary-key, so its kind of application fault 
not DBMS.
MySQL behaviour as you see is exactly like PostgreSQL in this case and 
it prevents it.


Cheers
Mohammad


Angel Pizarro wrote:

> kaustubh shinde wrote:
>
>> Our main criteria is to have a tool with MySQL support 
>
>
> OK, this is probably not a topic for this discussion, but I am going 
> to bring this up anyway.
>
> MySQL has a lot of "gotchas". See :
> http://sql-info.de/mysql/gotchas.html
>
> My personal favorite is that it does type checks on dates, but you can 
> still enter February 31st as a legal date.
>
> Unless you *absolutely* need to support MySQL I would look into 
> PostgreSQL as an alternative. Compare their list of gotchas:
> http://sql-info.de/postgresql/postgres-gotchas.html
> Much smaller, eh?
> hasta luego
> Angel
>
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by: SourceForge.net Broadband
> Sign-up now for SourceForge Broadband and get the fastest
> 6.0/768 connection for only $19.95/mo for the first 3 months!
> http://ads.osdn.com/?ad_id=2562&alloc_id=6184&op=click
> _______________________________________________
> Mged-mage mailing list
> Mge...@li...
> https://lists.sourceforge.net/lists/listinfo/mged-mage
>