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How to call the parent class in VFP?
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Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Divers
Thread ID:
00024551
Message ID:
00026720
Vues:
55
>>>>>>-- snip --
>>Bret:
>>I like to use Primary keys that are invisible to the user, and therefore do not depend on user input in any fashion. Certainly you need to have a field with your 'massaged' item_no data for indexing purposes, but does this really need to be your primary key? You can have multiple indexes, after all, and use them in different places.
>>
>>The biggest problem I see is that this field will remain blank after a new record is added until the user enters the correct item_no and then the data is re-entered (in the valid() event?) into your key field. If 2 users add records close together, the second may be trying to add a record with an empty key field when one already exists.
>>
>>Barbara
>Would pessimistic row buffering avoid an error here? I think my colleagues are pessimists about such things anyway.

Bret, I don't think pessimistic buffering would help, because a second user would be ADDING a record, not ACCESSING an existing record, so there would be no lock. And when they did an APPEND BLANK, they'd still have two records with blank primary keys.

Barbara
Barbara Paltiel, Paltiel Inc.
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