What if

What if... 
Firefox would let you start different browser profiles:

• Light, for super-fast web browsing, with only the extensions you need to turn the web upside-down in the minimum amount of time
• Work, surfing with all the tools you need to accomplish your duties in half the time
• Developer, the fox you are used to when it comes to play hard with code (and not to mention the add-ons that make it simple writing it...)
• ... other profiles, that you create on your own and share with your friends
  

What if...
Firefox could start these different profiles all at once, in different processes, for the best performance.

What if...
Firefox would let the different profiles seamlessly communicate one with the other, moving tabs from Light to Work and then to Developer and viceversa.

What if...
Firefox will be like this.
There will still be room for a different browser in your dreams?

Luca is behind some of these ideas. Thanks!

Blog redesign

I spent 3-4 hours redesigning this blog. Thanks for the "fleur" template to J. Maloney and Blogcrowds.
Let me know if you like it.

MySQL foreign keys (MySQL Error Nr. 1005)

12-09-2009 - 12:00
UPDATE:
Well, it seems to me that this topic deserves some more attention, so I'm going to investigate it thoroughly.
From this page I found that:

a table [...] must have indexes on the referenced keys. If these are not satisfied [read: "if they are not present for those keys"], MySQL returns error number 1005 and refers to error 150 in the error message.

More in detail, in the rest of the update I'm assuming the following command (as it is reported on the same page I linked above) as reference:

[CONSTRAINT [symbol]] FOREIGN KEY
 [index_name] (index_col_name, ...)
 REFERENCES tbl_name (index_col_name,...)
 [ON DELETE reference_option]
 [ON UPDATE reference_option]

@Dhruva Sagar: I think you were talking about this one:

If the CONSTRAINT symbol clause is given, the symbol value must be unique in the database. If the clause is not given, InnoDB creates the name automatically.

@payal: Check this (same page as above...):

InnoDB supports foreign key references within a table. In these cases, “child table records” really refers to dependent records within the same table.

Furthermore I suggest using the following command to check when errors occur: SHOW ENGINE INNODB STATUS, which displays a detailed explanation of the most recent foreign key error in the server.
I'm trying to replicate this error today; I'll drop you the results as soon as I can.


----------------- old updates -----------------

27-08-2007 - 10:08 (OLD UPDATE!!!)

UPDATE:
It seems the problem is caused by the "ON UPDATE" and "ON DELETE" clauses: they have to be set to the same policy, i.e. you have to write "ADD CONSTRAINT 'new_fk_constraint' FOREIGN KEY 'new_fk_constraint' ('fieldA1') REFERENCES 'tableB' ('fieldB2') ON DELETE RESTRICT ON UPDATE RESTRICT" or "ON DELETE UPDATE ON UPDATE UPDATE", while "ON DELETE SET NULL ON UPDATE RESTRICT" won't work.
Indexes are not the cause of the problem: when you create a foreign key an index for the field involved on the foreign key is automatically created by the MySQL environment, so you don't need to manually create it before adding the foreign key (read: "Bull-Shit at 09:41, Good-Shit at 10:08").

27-08-2007 - 09:41 (OLD UPDATE!!!)
If you want to place a foreign key from field 1 on table A to field 2 on table B, first of all you need to create an index for the field 1 on table A.
If you don't create the index before attempting to create the foreign key you are likely to be stopped by the error "MySQL Error Nr. 1005- Can't create table...".

I experienced this situation while using InnoDB.