Hi!
>>>>> "Arjen" == Arjen G Lentz <[EMAIL PROTECTED]> writes:
<cut>
>> The problem is, how would you add a new bus and a new driver to the
>> database? Whichever one is added first, you're going to get an error
>> because its counterpart doesn't exist yet, violating referential integrity.
>>
>> You could always relax the NOT NULL constraint, but that might not be
>> desirable if you want to be consistent with the real-world situation that
>> your database describes. Is there a way to update two tables at the exact
>> same time so that referential integrity never gets violated?
Arjen> You can do this by putting the two updates inside a transaction, using the
Arjen> InnoDB table type instead of MyISAM.
Arjen> No problem.
Note first that foreign keys can't be used to solve all problems of
references integrity as a foreign key can only refer to a primary key
in another table.
I am quite sure that the referential integrity is checked per
statement, not per transactions. (Which is a common thing in many
databases).
If this is the case, then you can't solve this by wrapping the updates
in two transactions.
Regards,
Monty
PS: Sorry, but I didn't have time to test this properly as I am
answering this on my laptop...
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