asked on Optional Foreign Key Constraints?
There are three tables: bugs, comments and attachments.
A comment is always associated with a bug. (bugs have comments).
An attachment will always be associated with a comment (attachments belong to specific comments)
BUT a comment will not always have an attachment. (Like cookies, attachments are a sometimes food).
How do I setup the foreign key constraints here?
Pretty sure this won't work because if I post a comment without an attachment, it will fail...
A comment is always associated with a bug. (bugs have comments).
An attachment will always be associated with a comment (attachments belong to specific comments)
BUT a comment will not always have an attachment. (Like cookies, attachments are a sometimes food).
How do I setup the foreign key constraints here?
Pretty sure this won't work because if I post a comment without an attachment, it will fail...
CONSTRAINT `fk_comments_bugs1`
FOREIGN KEY (`comments_bug`)
REFERENCES `bugreport`.`bugs` (`bugs_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_comments_attachments1`
FOREIGN KEY (`comments_attachment`)
REFERENCES `bugreport`.`attachments` (`attachments_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
MySQL ServerPHP
Last Comment
Kent Olsen
No, the FK is to prevent you from entering an attachment without a comment. You should have no problem creating a comment without an attachment.
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