should i do that ?

[asmith]

for registering user, i want to insert 2 rows in 2 diffrent tables for each user,

i have put in the code that if the row 1 couldn't insert into table 1  , so don't insert row 2 in the table 2.

and if row 1 inserted, but row 2 couln't, then delete row 1 .

how much precent it is the posibilty that inserting to mysql tables fails ? in other words , do i really have to do such coding ?

 

[fenway]

This is what's known as a "transaction" -- MyISAM tables don't support this, but InnoDB (and others) do.  If anthing "inside" fails, you simply rollback, and then it's like it's never happened (though you still need to handle user notification).

 

Inserting won't "fail" unless there's a DB error (e.g. server crashes), you're statement isn't valid (shouldn't ever happen on a production server), etc....

[asmith]

so it is a thing that happens 1 in a million ?

[fenway]

It's as reliable as any other reliable multi-threaded server application -- if you can't afford any failure, that's a different story.