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Microsoft SQL Server
A trigger fires ONCE, no matter how may records are being updated. Those lines ensure that each parent that is updated gets it's childcount field updated.
>Thanks Bob.
>
>I did run the sql manually so the update alone worked fine.
>WRT your sample, I don't understand what the last two lines accomplish
>
>from parent
> join inserted on parent.pcode=inserted.pcode
>
>If its not too much trouble, could you attempt to enlighten me?
>
>Thanks,
>-Isaac
>
>
>>update parent
>>set childcount =
>> (select COUNT(item_code)
>> from child
>> where child.pcode = parent.pcode)
>>from parent
>>
>>If you do this in an insert trigger to the child you can do something like...
>>
>>update parent
>>set childcount =
>> (select COUNT(item_code)
>> from child
>> where child.pcode = parent.pcode)
>>from parent
>> join inserted on parent.pcode=inserted.pcode
>>
>>**********
>>BOb
>>
>>
>>>Hello,
>>>
>>>I'm trying to figure out the syntax for updating a count column based on the child table count.
>>>Parent table has the columns columns pcode, childcount
>>>Child table has the columns pcode, childname
>>>
>>>I'm thinking I want to do something like the following, though I'm stuck
>>>figuring out how to finish the sql
>>>
>>>update parent
>>>set childcount =
>>> (select COUNT(item_code)
>>> from child
>>> where child.pcode = parent.pcode)
>>>
>>>How do I tell the subquery what the parent.pcode is?
>>>
>>>Any suggestions would be greatly appreciated.
>>>
>>>Thanks,
>>>-Isaac
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