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Sells, Laverty and Flasko: Entity Framework 4, oData and PDC10

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The Discussion

  • User profile image

    Awesome news! This Video got me really into oData, startting to understand it. If I would now want to find a relationship between Associated Press and UNdata I could do it more easily because there is onyl one data exchange protocol to learn. Odata.

    Also: reminds me a lot of the first video of LIVE MESH ever. It also gave the developper the choice to choose the way the results were formatted. And now that windows live has it, its kind of the Mesh API and Live Framework returned (without the sync part of the api then).

    If Windows Live Devices would have an oData feed it would be awesome. It would be like making the 'device ring' expandeble in the old Live Mesh. (The old vision of the car that connected to the cloud oData feed to sync music or the printer that printed photo's from your skydrive). It has a solid foundation now!

    If a printer consumes a odata feed from my skydrive I could print my pictures directly.
    If a printer was added to the 'devices feed' then it would somehow be linked togetter in the oData tree with the other data. And anyone in the feed you print to my printer. Possibilities seem endless again.

    Thx for this great video charles! Looking forward to PCD10 !

  • User profile image

    classic channel9.. great to see Smiley

    new EF stuff looks really great. o think one of the obstacles to EF adoption as hasways been that you had to rely on a propriatary tool (VS and its designer) to be productive in EF.. code first really gives me at least a better feeling of ownership of my own product and i dont have to live in fear that there will be be compat issues when the next version of VS drops.

    for me it also better reflects the way i write code, starting with the domain objects. that is something i do way before i think about a presistance technology. in the old EF id have to reimplement all my domain objets in the EF designer and that sucked Smiley

    Odata is also really cool. whats also cool is the way you expose it. (hopefully that hasnt changed since last pdc when i asked the question). simply exposing a IQueryable in a service contract. now thats awsome..

    one thing i would ask with odata though is how to prevent too much data being sent. i for instance have a database with tables with milions of rows, and i want to avoid a situation where someone asks my odata feed for something and unintentially downloads all those rows.

    of course people can make errors but i ran into this with the netflix odata service. excel was just building the model but it seemed like a whole lot of data about movies was downloaded..

  • User profile image

    I am not so sure that I am not too set in my ways. If I am writing a database program, then everything is thought out, schemas and all, though your modern/novice programmers that like classes may prefer the code first, autogeneration of classes.

    I detest the EF object model, compared with Linq. If for example, you have two related tables you have to use strings of tables names, wheras with Linq to SQL you have the dataloadoptions.

    I am not really sure Chris Sells has the time to read old threads here on channel 9, but I think I outlined my feelings succinctly.

    I think t4 templates are an insanely powerful addition, especially when working in n-tier applications, and hope MVVM frameworks based around data can start to include them with EF as there is an incedible amount of code duplication so if Chris and the tem could come up with a way to have EF 5 create MVVM compliant datawrappers, then that surely would increase the popularityy as right now Linq to SQL does exactly the same job, is better designed and far simpler

  • User profile image

    Awesome video guys! Demystifying EF4 code first and OData. Also, thanks for the Dallas reference at the end. I've been looking for a way to get at to do some F#/ WPF visualizations. Now I can use OData!

  • User profile image


    As a service writer, you can limit the number of rows sent out with every request at a set level via Server Driven Paging limits. This limit is absolute and is opaque to the client developers. You can keep increasing or decreasing limits without breaking your client.

    You can read more about SDP here :

    As a client developer, you can limit  the number of rows you download via the $top query option.You can also reshape the results to specify which columns you want in the results via Linq Projections or using using the $select query option.

    Query Projections on MSDN:


  • User profile image


    cool, thanks Smiley

  • User profile image

    Sim, como um escritor do serviço, você pode limitar o número de linhas enviado com cada solicitação em um nível definido via limites Server Driven Paging. Esse limite é absoluto e é opaco para os desenvolvedores do cliente. Você pode continuar a aumentar ou a diminuir os limites sem quebrar o seu cliente, muito obrigado! meus projetos:

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