Level Extreme platform
Subscription
Corporate profile
Products & Services
Support
Legal
Français
Finding duplicate keys
Message
From
14/01/1999 12:09:50
 
 
General information
Forum:
Visual FoxPro
Category:
Databases,Tables, Views, Indexing and SQL syntax
Miscellaneous
Thread ID:
00176022
Message ID:
00176030
Views:
31
>>>When the user enters a new unit, or modifies the current one, I need to save it. But I don't want it to save if the unit is a duplicate. I also want to be the one to give the error message.
>>>
>>>Currently, I have a complicated IF to determine if the unit has changed and then I scan through the table to see if it's already there. I also have to make sure I don't get an error if the user changes the unit name, then changes it back, because then it will have changed AND be in the table already.
>>>
>>>It seems like there should be a simpler way of doing this. I've made the unit name a candidate index. Can I do the row update and have it tell me if the key's uniqueness was violated?
>>>
>>>Is there some way to put this in the database so whenever a user tries to save a duplicate unit, my error message comes up an the save is rejected?
>>>
>>>Thanks,
>>>
>>>-Michelle
>>
>>I think Candidate Tag is normal solution here.
>
>Candidate Tag? Is that different than making a field a candidate key? If not, and since it's already a candidate key, I don't see how that's a solution...
>
No, it's the same :). What's wrong you found? When you try to save a record, VFP will raise uniqueness violation error and you may trap it nicely.
Edward Pikman
Independent Consultant
Previous
Next
Reply
Map
View

Click here to load this message in the networking platform