Deleting using Relationships problem

I am in the process of converting an Access DB over to MySQL which up until now has been a relatively simple task.
The problem that I am faced with now is that MySQL doesn't appear to actually support any sort of relationship system in the same way to Access. For example, imagine I have three tables:

UserDetailsTable
UserBiogTable
UserCommentsTable

complete with the relevant information in each one.
With Access, if I set up relationships I am able to delete the a record in the UserTable and all the related records in UserBiogTable and UserCommentsTable are automatically deleted. Hardly rocket science but very useful.

It appears however that this is impossible in MySQL unless I manually delete all associated records.
Is this right or am i missing something? I was under the impression that MySQL was a RDBMS but this appears not to be correct?????

Thanks in advance, Chris.



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