OK, I've made some changes, and I'm still trying to figure out this foreign key stuff. This time, I'll focus on just two tables, named "continents" and "nations."
I put screen shots of their structure and some sample rows online at http://www.geoworld.org/try.gif It sounds like non-repeating numerals are generally preferred for use as primary keys, but letters can be used. I'd greatly prefer to use letters, because it's much more easier for me to match them with their respective countries and continents when working on related tables. But if this experiment fizzles out, too, I may abandon abbreviations and just use numerals for my primary keys. At any rate, I want to join the continents and nations tables via a shared column named "CCode." In the continents table, it's designated a foreign key, and none of the codes repeat. In the nations table, some of the values do repeat - obviously, Canada and the U.S. both merit the abbreviation na (North America). If I understand correctly, I have to designate a column a unique index BEFORE I can make it a foreign key. I tried designating the CCode field on the table "nations" a unique index, without success. Is that because of the repeating values? I then tried to designate a column with non-repeating numerals a unique index, but that didn't work, either. I finally learned how to create a foreign key with phpMyAdmin, but that doesn't work, either. I put screenshots of my trials online at http://www.geoworld.org/fk.gif (The second table was then named nations2, but I've since renamed it to nations.) If the only solution is to make all my primary keys non-repeating numerals, then I'll go that route. If there are other problems, then I'd like to know if anyone on this list knows how to designate foreign keys with either MySQL-Front or SQLyog. I've used them as workarounds for other problems I have with phpMyAdmin, but their Help sections are worthless for foreign keys. Thanks. __________________________________ Do you Yahoo!? Yahoo! Movies - Buy advance tickets for 'Shrek 2' http://movies.yahoo.com/showtimes/movie?mid=1808405861 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
