If you, like me, are using the free Control Center (CC) application that comes from the fine people at MySQL AB, the default for an INT field is 11 bytes, not 6. I somehow got the sizes of the database field mismatched when I followed the tutorial, and when the Recipe and the Category were trying to shake hands they were unable to find each other.
But, after I edited the id column to a standard size of 6 bytes to the INT, my data disappeared from the tables. I must have hit some button, the application could not be that unstable.
No harm done, after I added the data agagin, the tables/objects found each other like a charm.
Now when I try and find the link to the CC application, it seems it has evolved into the MySQL Administrator (which is also released under the GPL), which is a 4.7 mb download from MySQL's developer page for downloads.
Man! It looks slick. OK, that was my 2 cents.
OK, now I gotta get into the study tasks before Part 2 of this tutorial is released! Keep up the great work, Curt.