>>>In a multiuser environment, it is difficult to use PACK to remove a deleted record. To work around this problem, we can recycle the deleted records. In that case, we do not need to physically remove those deleted records. But in VFP if the table has primary index the deleted records will have a problem with the "uniqueness". I wonder whether there is a simple way to work around it.
>>
>>Sure. Change the key when you delete a record. Depending on how you generate unique keys, you can set a rule to have unique "real" keys and unique "deleted" keys.
>>
>>Vlad
>
>Or, when you reclaim a deleted record you can change the key id to the next available generated id.
This works fine with surrogate keys. But if the key is part of the business info and the deleted keys must be reused, it's better to change it at the delete moment.
Vlad
Précédent
Répondre
Voir le fil de ce thread
Voir le fil de ce thread à partir de ce message seulement
Voir tous les messages de ce thread
Voir tous les messages de ce thread à partir de ce message seulement