C# entity framework MVC second run error

Question

I am creating db and initializing data with code below, if DB doesnt exist, it creates db and populate it, when I run application second time I get error

Cannot drop database "aspnet-app" because it is currently in use.

Application_start, with initializations

protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();

        WebApiConfig.Register(GlobalConfiguration.Configuration);
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);

        Database.SetInitializer(new ComponentDbInitialize());
        ComputerContext context = new ComputerContext();
        context.Database.Initialize(true); //here it fails on second run
        context.SaveChanges();
    }

ComputerContext

 public ComputerContext():base("name=Default")
    {
    }
    public DbSet<Computer> Computers { get; set; }
    public DbSet<Motherboard> Motherboards { get; set; }
    public DbSet<CPU> CPUs { get; set; }
    public DbSet<Case> Cases { get; set; }
    public DbSet<HDD> HDDs { get; set; }
    public DbSet<RAM> RAMs { get; set; }
    public DbSet<GPU> GPUs { get; set; }
    public DbSet<PSU> PSUs { get; set; }
}

Initialize class

public class ComponentDbInitialize : DropCreateDatabaseAlways<ComputerContext>
{
    protected override void Seed(ComputerContext context)
    {
        GetCpu().ForEach(p => context.CPUs.Add(p));
        GetGpu().ForEach(p => context.GPUs.Add(p));
        GetCase().ForEach(p => context.Cases.Add(p));
        GetHdd().ForEach(p => context.HDDs.Add(p));
        GetMb().ForEach(p => context.Motherboards.Add(p));
        GetPsu().ForEach(p => context.PSUs.Add(p));
        GetRam().ForEach(p => context.RAMs.Add(p));
        context.SaveChanges();
    }
private static List<CPU> GetCpu() .....
private static List<GPU> GetGpu().....
private static List<HDD> GetHdd()....
private static List<Case> GetCase()....
private static List<Motherboard> GetMb()....
private static List<PSU> GetPsu()....
private static List<RAM> GetRam()....

I get same error even with

context.Database.Initialize(false);

Thank you for any help/advice

DavidG · Accepted Answer · 2015-06-23 12:02:18Z

1

Your initialiser is using the DropCreateDatabaseAlways class which, as it suggests, drops that database every time the application is initialised.

Instead perhaps you could use CreateDatabaseIfNotExists or DropCreateDatabaseIfModelChanges:

public class ComponentDbInitialize : CreateDatabaseIfNotExists<ComputerContext>
{

}

answered Jun 23, 2015 at 12:02

DavidG

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3 Comments

user2925656 Over a year ago

Thank you very much, solved problem. In every tutorial I've been following they used this DropCreateDatabaseAlways Strategy, my bad. By the way, is this the correct way to create/manipulate DB as I do in my code ? And why does it fails when it should delete DB? Both of your strategies works like a charm. Thank you again.

DavidG Over a year ago

This is a reasonable way to manipulate your databases. The reason for the fail was the a connection was open to the database already, possibly this is Visual Studio or your app itself.

user2925656 Over a year ago

I accepted your answer just had to wait some 10minutes cooldown, your answer came too fast ;) I just found out it has something to do with SSMS in visual studio and workaround is to set Pooling to false, but I rather solve problem then work it around. Thank you for your time.

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