In table design, highlight all fields for the key and click the key button.
-------------- Ian Skinner Web Programmer BloodSource www.BloodSource.org Sacramento, CA "C code. C code run. Run code run. Please!" - Cynthia Dunning ....-----Original Message----- ....From: Saturday (Stuart Kidd) [mailto:[EMAIL PROTECTED] ....Sent: Thursday, July 14, 2005 4:51 PM ....To: CF-Talk ....Subject: Re: 2 Primary Keys .... ....Just one other thing however, how do i create the compound key via ....Enterprise Manager, can I do it through that? I'm on shared hosting ....with hostmysite.com. .... ....Thanks, .... ....Stuart .... .... ....On 15 Jul 2005, at 00:52, Dave Watts wrote: .... ....>> I want to add a row in a join table which i don't want to be ....>> duplicated ever. ....>> ....>> So i have my tableID, table1ID, table2ID - if table1ID = 24 ....>> and table2ID = 35 i don't want there to ever be a reoccurence of ....>> them. I guess i have to set both of those fields (table1ID, table2ID) ....>> to primary keys, but how can i do that? Do i do it in ms-sql or via ....>> Coldfusion somehow? ....>> ....> ....> As a bunch of people have already mentioned, you can create ....> compound keys ....> within your database. A compound key consists of more than one ....> field. If you ....> go that route, you really don't need the "tableID" field any more ....> (assuming ....> that field is currently being used as your primary key) - you can ....> just make ....> the combination of table1ID and table2ID your primary key. ....> ....> One disadvantage of this is that, if you have other tables which are ....> dependent upon this one, those tables will need to contain both ....> fields for ....> use as a foreign key. However, in all likelihood you don't have any ....> other ....> tables which are dependent upon this one, but rather this table is ....> dependent ....> upon two other tables - this kind of table is often called a ....> linking or ....> intersection table. The "middle" table in a many-to-many relationship ....> typically follows this pattern. ....> ....> Another disadvantage of this is that you won't be able to store ....> historical ....> relationship data - either a relationship exists now, or it ....> doesn't. If you ....> do want to store historical data, you'd need to keep the current ....> "tableID" ....> as your primary key, or add a third field to your two-field primary ....> key - ....> the value of that third field would have to be different for any ....> two rows ....> that have the same values for the other two fields. ....> ....> ....>> If i do it via MS-SQL then won't it pop an error up in the code if ....>> it happens? ....>> ....> ....> Yes, like any other invalid query you might run. It's up to you to ....> catch and ....> resolve those errors appropriately within your code. ....> ....> Dave Watts, CTO, Fig Leaf Software ....> http://www.figleaf.com/ ....> ....> Fig Leaf Software provides the highest caliber vendor-authorized ....> instruction at our training centers in Washington DC, Atlanta, ....> Chicago, Baltimore, Northern Virginia, or on-site at your location. ....> Visit http://training.figleaf.com/ for more information! ....> ....> ....> .... .... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Logware (www.logware.us): a new and convenient web-based time tracking application. Start tracking and documenting hours spent on a project or with a client with Logware today. Try it for free with a 15 day trial account. http://www.houseoffusion.com/banners/view.cfm?bannerid=67 Message: http://www.houseoffusion.com/lists.cfm/link=i:4:211946 Archives: http://www.houseoffusion.com/cf_lists/threads.cfm/4 Subscription: http://www.houseoffusion.com/lists.cfm/link=s:4 Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.4 Donations & Support: http://www.houseoffusion.com/tiny.cfm/54
