Re: DataTable.Load()
- From: "Cowboy \(Gregory A. Beamer\)" <NoSpamMgbworld@xxxxxxxxxxxxxxxxxx>
- Date: Fri, 7 Mar 2008 10:30:09 -0600
That is what Wen was saying: You should not see any open and close. I would
take this further and say "I would be absolutely shocked to see any new
connections", as the under-the-hood operations are not transparent and do
not bubble up to the connection level.
What Bill was talking about is the way SQL Server handles things, which is
not something the average developer would ever get into. What Bill was
stating is that communication will be in blocks. This does not mean a new
connection opening each time, as the Reader is a firehose cursor. As you run
through it and get past what is cached, you will get another request.
In normal operations, you run through a Reader like so:
while(Reader.Read()
{
}
This operation takes a fraction of a second to complete, at least in most
applications, as you do not want to leave a connection dangling.
Now, back to DataTable.Load(). It is still using a Reader, underneath the
hood. As it loads, the data is loaded in blocks. As more info is needed,
more blocks of data are requested, until complete. This is transparent to
the user, as the entire Load() operation should normally be in milliseconds.
Sure, you can load a boatload of data, but, other than reporting, there are
few reasons to do that.
--
Gregory A. Beamer
MVP, MCP: +I, SE, SD, DBA
*************************************************
| Think outside the box!
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"Scott M." <smar@xxxxxxxxxxxxx> wrote in message
news:%23xGM%23$EgIHA.5296@xxxxxxxxxxxxxxxxxxxxxxx
Why would you see the connection opening and closing on the server during
a DataReader's read operations? Wouldn't it just stay open until .NET
asks for it to be closed?
""Wen Yuan Wang [MSFT]"" <v-wywang@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:MmwG%23aDgIHA.6844@xxxxxxxxxxxxxxxxxxxxxxxxx
Thanks for William and Cor's reply.
Hello Scott,
In my opinion, there is only one round-trip in Load method. If you use
profile to trace what happens on SQL server, I believe you won't find any
connection open/close event when loading.
But, on ado.net side, .net runtime get data from DB server by cache side
blocks.
The implement of Load method should be something like blow:
While (DataReader.read())
{Table.Rows[row][column]=DataReader.getFiled(int);}
Hope this helps. Please feel free to let me know if you have more
concern.
We are glad to assist you.
Have a great day,
Best regards,
Wen Yuan
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- References:
- DataTable.Load()
- From: Scott M.
- Re: DataTable.Load()
- From: Scott M.
- Re: DataTable.Load()
- From: "Wen Yuan Wang [MSFT]"
- Re: DataTable.Load()
- From: Scott M.
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