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Старый 28.10.2006, 16:40   #1  
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Fred Shen: Always use recId to know if a select statement returns a record
Источник: http://fredshen.spaces.live.com/Blog...E4E3!161.entry
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In Axapta, there are two options to know if a select statement returns a record.
Option 1:
    select purchTable where
        purchTable.purchId == "Do not exist";
    if (purchTable)
    {
         …//Your logic here
    }

Option 2:
    select purchTable where
        purchTable.purchId == "Do not exist";
    if (purchTable.recId)
    {
         …//Your logic here
    }

It is strongly recommended to use recId. Because when working with aggregate functions in select statement. Table reference will always exist no matter a record is returned or not, but recId will be 0.
e.g.
    select count(purchId) purchTable where
        purchTable.purchId == "Do not exist";
    if (purchTable)
    {
        info("The record exists!");
    }

It will present the user "The record exist!" even there is no record returned.




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Источник: http://fredshen.spaces.live.com/Blog...E4E3!161.entry