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Best way to check for and/or create connection to DB
Message
De
08/01/2013 12:26:45
 
 
À
08/01/2013 11:55:08
Information générale
Forum:
ASP.NET
Catégorie:
Bases de données
Versions des environnements
Environment:
VB 9.0
OS:
Windows 7
Network:
Windows 2008 Server
Database:
MS SQL Server
Application:
Desktop
Divers
Thread ID:
01561620
Message ID:
01561738
Vues:
41
>>>>>IMO if you are assuming you will be doing a pile of queries in a short amount of time, leave the handle open.
>>>>>
>>>>>If the queries will be spread out over time (waiting for user action, etc) - open and close as needed.
>>>>
>>>>In the Signon screen, there's a call to get Student Name and Instructor Name from the Student Control Number and another to check password.
>>>>
>>>>In the DispQuestion screen, between each question it
>>>>
>>>>1) 'Scores' the answer
>>>>2) Stores QuestionID, Answer, CorrectAnswer, Time Answered
>>>>3) Checks to see if the next Question is an Experimental Item, if so, skips #4, selects the next ExpItemID
>>>>4) Calculates an Information Function on all possible next questions, based on what's needed next and what gives the most information.
>>>>5) Displays the next question.
>>>>
>>>>Would there be any performance hit to create/open for each call...and does a 'Close' clear the connection from memory. IE, I don't want to be creating multiple copies of QConn for each student.
>>>
>>>Closing a connection leaves the connection in memory. You can Open it again.
>>>
>>>If it is scoped to a SQLCommand or a function/procedure that goes out of scope then the connection goes away with it.
>>>
>>>If you are rolling through hundreds or thousands of questions quickly (like - per second), then there will be a performance hit. Still not horribly bad, but there will be one.
>>>
>>>You can watch and get metrics on the running code in VS. You might want to watch this to get a good idea of how your particular app is running.
>>
>>Thanks for the info. As for throughput, we're talking hundreds of questions per second per session. Average time to answer per student is (roughly) 15-30 seconds and as this is a timed test, I want to keep the time between answer and display of next question as short as possible.
>
>
>You can always fetch the next question (and not display it yet) after you display the current question. Sort of using the 15-30 seconds time frame.
>So you have the next question long before the current one gets answered
>
>
>Update - or even better - fetch all the questions in advance in one go, then display them one by one

Can't - it's an adaptive test, I don't know what the next question is until they answer the last one.
"You don't manage people. You manage things - people you lead" Adm. Grace Hopper
Pflugerville, between a Rock and a Weird Place
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