fast linq to sql query to table with images

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Good day!
Help plz...

how i can correctly select info from DB...
example...

i have
1 table Cars where have Id, VIN
1 tabke CarImages where I have id, carid (from Car table) and Image as binary data

I need to build sample XML struct:

XML

<Cars>
<Car id="1" vin="CarVin13simbol" PhotosCount="2">
<Car id="2" vin="CarVin13simbol" PhotosCount="10">
<Car id="3" vin="CarVin13simbol" PhotosCount="0">
</Cars>

How correctly build linq query? All i try - download all data (and images too) by var QueryData example

C#

_dc.Cars.First(x => x.id == 1).CarPhotos.Count()

many time my program executing and many memory in use (sometimes outofmemoryexeption)

Help plz... sorry for English... bad know it :)

Posted 12-Mar-15 3:07am

Member 11519571

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Richard Deeming · Answer 1 · 2015-03-12T03:39:00

Solution 1

Try something like this:

C#

var allCars = _dc.Cars.Select(x => new 
{ 
    x.id, 
    x.vin, 
    PhotosCount = x.CarPhotos.Count() 
});

var allCarsXml = allCars.AsEnumerable().Select(x => new XElement("Car",
    new XAttribute("id", x.id),
    new XAttribute("vin", x.vin),
    new XAttribute("PhotosCount", x.PhotosCount)
);

var xml = new XDocument(new XStreamingElement("Cars", allCarsXml));

Posted 12-Mar-15 3:39am

Richard Deeming

Updated 12-Mar-15 3:40am

v2

Comments

Member 11519571 12-Mar-15 11:00am

hm... thx for code example...
hm... tell me plz this code:
dc.Cars.First(p => p.Id == CarId).CarPhotos.Count()
download from BD images? Or this cide will be fast?

Richard Deeming 12-Mar-15 16:44pm

Your code will load the full car details into memory, then load the entire collection of photos for the car into memory, and then count the photos.

The code I posted will be translated into a SQL query that returns the number of images per car, without loading any of the images into your application's memory.