Question

I’m creating a database where users can enter some Error Reports and we can view them. I’m making these database with C# in the ASP MVC 3 .NET framework (as the tags imply). Each Error Report has a unique ID, dubbed ReportId, thus none of them are stored under the same Id. However, whenever a User creates a new Error, I pass their User Name and store it in with the rest of the report (I use User.Identity.Name.ToString() to get their name and store it as a string). I know how to get a single item from the data using a lambda expression, like so:

db.DBSetName.Single(g => g.Name == genre)

The above code is based on an MVC 3 tutorial (The Movie Store one) provided by ASP. This was how they taught me how to do it.

My major question is: is there a member function like the .Single one that will parse through the whole database and only output database entries whose stored User Name matches that of the currently logged in user’s? Then, I can use this to restrict User’s to being only able to edit their own entries, since only their entries would be passed to the User’s View.

What would be the best way to implement this? Since the ReportId will not be changed, a new data structure can be created to store the user’s Errors and passed through to the Index (or Home) View of that particular controller. From there they should be able to click any edit link, which will pass the stored ReportId back to the Edit Action of this particular controller, which can then search the entire database for it. Am I right in assuming this would work? And would this be ideal, given that the other items in the database are NOT passed through to the Index in this method, meaning the User does not have access to the other items’ ReportId’s, which the user needs to pass into the Edit Action for it to work? If this is ideal, this is the method that requires me to know how to parse through a database and grab every element that fits a particular description (stored User Name matches User’s current User Name).

Or would a better approach be to pass the whole database to the Index View and only output the database entries that have User Name values that match the current logged in user’s? I guess this could be done in a foreach loop with a nested if loop, like so:

@foreach(var item in db.Reports)
{
    if(item.UserName == User.Identity.Name.ToString())
    {
        ...code to output table...
    }
}

But this passes the whole database which gives the user a lot more info than they need. It also gives them potential access to info I don’t want them to have. However, I don’t have to make a new data structure or database, which should lower server memory usage and fetch time, right? Or are databases passed by copy? If so, this method seems kinda dumb. However, I don’t know if the first method would fracture the database potentially, this one certainly would not. Also don’t remember if I NEED an else statement in C#, I’m more familiar with C++, where you don’t need one and you also don’t need {}’s for single line if’s, if I need one: please don’t judge me too harshly on it!

Small note: I am using CRUD Controllers made with the Entity First Framework in order to edit my database. As such, all creation, reading, updating, and deletion code has been provided for me. I have chosen not to add such basic, common code. If it is needed, I can add it. I will add what the Edit Action looks like:

public ActionResult Edit(string id)
{
    Report report = db.Reports.Find(id);
    return View(report);
}

It accepts a string as an id, ReportId is the id used and it IS a string. It is a randomly generated GUID string made with the GUID.NewGuid().ToString() function. I will also be doing the comparison of names with:

Model.UserName == User.Identity.Name.ToString()

Which was shown earlier. Sorry if this is too much text, I wanted to provide as much info as possible and not make anyone mad. If more info is needed, it can certainly be provided. So at the end of the post, the major question actually comes down to: which of the above two methods is best? And, if it’s the first one, how do I implement something like that?

Thanks for your help!

Answer 1

Unless I’m completely misunderstanding you, you just want .Where()

Like this:

var reports = db.Reports.Where(r => r.genre == inputGenre);

This would get you an IEnumerable of Report, which you could then use however you wish.