I just solved my own question, but thought I'd might still be helpful for others to read so decided to post it anyway.
I am trying to get started with azure development and am currently at the stage of getting the database up and running. After a few hickups I achieved the following:
installed VS2012, MSSQLSERVER2012, Azure SDK .NET, EntityFramework 6.0.0 alpha and a bunch of other things
wrote my first entities (code first) and generated a database out of it.
The last thing I'd like to see before I pick up the next challenge is to actually add something to my newly created database first. I'd thought the easiest way would be writing a test in nunit.
Here's what I got so far...
The entity class User:
namespace Models.Users
{
public class User
{
public int Id { get; set; }
public string Name { get; set; }
public string EmailAddress { get; set; }
}
}
The entity class UsersDb:
using System.Data.Entity;
namespace Models.Users
{
public class UsersDb : DbContext
{
public DbSet<User> Users { get; set; }
}
}
Generated the database with the following PS commands:
enable-migrations -ProjectName Models -ContextTypeName Models.Users.UsersDb
add-migration -ProjectName Models Initial
update-database -ProjectName Models
Finally, I wrote the following unit test
using Models.Users;
using NUnit.Framework;
namespace Tests
{
[TestFixture]
public class DatabaseTests
{
[Test]
public void AddUserTest()
{
var users = new UsersDb();
var user = new User
{
Id = 1,
Name = "test",
EmailAddress = "test#gmail.com"
};
users.Users.Add(user);
users.SaveChanges();
}
}
}
That test runs, but throws an exception I can't figure out.
System.InvalidOperationException : The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' for the 'System.Data.SqlClient' ADO.NET provider could not be loaded. Make sure the provider assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.
Solution
What I had to do to solve this, is open NuGet management (right click solution) and press the manage button on EntityFramework. In the dialog add a checkbox in front of your test solution, rebuild and go.
Now, I have a very small solution that creates a new user via a unit test and saves it into my database. A nice startup project which I can now start extending.
Solved the question while typing the question itself. Thought i'd still be useful as a reference for others.
Related
I'm following a guide for creating a simple code-first MVC, which uses data context scaffolding. After creating a model class file and adding a scaffolded item to the project, it instructs me to go to server explorer, hit "new connection", enter (localdb)\mssqllocaldb and from there, select my database name (PlanetContext (CodeFirstFinal.Models). After hitting "ok", I should be able to expand the tables in my server explorer and see the planet data table. However, my tables folder is empty. I followed the tutorial to the letter, so I'm unsure why this is happening.
Here is the code in my model:
namespace CodeFirstFinal4.Models
{
public class Planet
{
public int PlanetID { get; set; }
public string Name { get; set; }
}
public class PlanetContext: DbContext
{
public DbSet<Planet> Categories { get; set; }
}
}
As this is a very simple app, this is the only code so far, besides the scaffolded view. (For that, I right-clicked my project, selected "add scaffolded item" and MVC 5 Controller with views using EntityFramework. I then entered my model class, which is:
Planet (CodeFirstFinal4.Models)
and my data context class, which is: PlanetContext (CodeFirstFinal4.Models).
I'm not sure how helpful this information is, but I'm including it in case it helps. I'm pretty sure that the MvcScaffolding package is installed correctly, as well as EntityFramework. However, I simply can't get the data table to be generated after right clicking 'connect to database' under server explorer, entering my local server name, and selecting the database. Below is a screenshot of the tutorial, where his table shows up under the tables folder, within server explorer. Does anyone know what might be causing the failed generation of my own data table?
I'm pretty new to both Azure and code first. I have an app which works locally. I published the web project using the visual studio wizard. All worked well.
However its missing all the db tables.
I had a look at the connection string which has a "DefaultConnection". Locally its "Server=(localdb)\...".
In azure it appears as "Data Source=tcp:Sniipedb.database.windows.net,1433"
I have a db initializer which seeds the data but it only works locally.
My AppDBContext I assume should have created the db.
The actual error on the site online is "SqlException: Invalid object name 'Users'.
System.Data.SqlClient.SqlConnection.OnError(SqlException exception, bool breakConnection, Action wrapCloseInAction)"
When I look in the DB, however, there are no tables.
I'm making a simple chores app. Users is a DB table.
To create users I have the following:
within startup.cs
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<AppDBContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
services.AddTransient<IUserRepository, UserRepository>();
services.AddTransient<ITaskRepository, TaskRepository>();
services.AddMvc();
}
within the AppDBContext : DbContext
public DbSet<User> Users {Get; set;}
User is a simple class
public class User
{
[Required]
public string FirstName { get; set; }
[Required]
public string LastName { get; set; }
[Key]
public string EMailAddress { get; set; }
public ICollection<UserTask> UserTasks { get; set; }
}
I have a DBInitializer which seeds new users and saves the context.
This works flawlessly on the local machine.
The solution for me was to configure my Publish. Within the settings it has a "databases" option where the "use this connection string at runtime" was unchecked.
Also under "Entity Framework Migrations" the "Apply this migration on publish" was unchecked.
By checking those two, then saving and then publishing it worked.
I used this pluralsight video on MVC code first migrations to keep my default MVC IdentityDb context and create another context for custom tables. Since then I get an error trying to connect connecting to the database online:
CREATE DATABASE permission denied in database 'master'.
.........
It works locally. My connection string are correct and my context classes point to the right connection string name:
public class IdentityDb : IdentityDbContext<ApplicationUser>
{
public IdentityDb()
: base("DefaultConnection", throwIfV1Schema: false)
{
}
public static IdentityDb Create()
{
return new IdentityDb();
}
}
public class CustomDb : DbContext
{
public CustomDb() : base("DefaultConnection") { }
public DbSet<Inquiry> Inquiry { get; set; }
public DbSet<Product> Product { get; set; }
}
Connection string:
<add name="DefaultConnection" connectionString="server=***.db.1and1.com; initial catalog=***;uid=***;pwd=***" providerName="System.Data.SqlClient" />
I've read that the connection string name should be the same as the context class name but since I have two contexts I need a common name (DefaultConnection) which I've specified in the contexts.
It works connecting to my local database but not when its online so I did wonder if this would relate to the migration history table being up to date online and EF 6 trying to update the database but the entries in the migrations table match.
Any help appreciated.
* UPDATE *
I tried resetting the EF migrations with this guide thinking if the migrations where out of sync with the online DB it could result in EF trying to re-create the database causing this issue. However the problem still persists!
I have now added these lines to my context constructors respectively:
Database.SetInitializer<IdentityDb>(null);
Database.SetInitializer<CustomDb>(null);
This has stopped the error but kind of defeated the purpose of EF because I now have to remove it when creating migrations and manually script the changes to the online DB, then put it back in for the site to work online.
I really have no luck with the EF every time. This time it looks like this:
First time i created a context i had an error like:
Invalid object name 'dbo.TableName1'
After this setting the Database Initializer to CreateDatabaseIfNotExists T it did the trick.
Next i created a different context, which was changed at some point of the development. So this time i keep getting this error:
The model backing the 'NewContext' context has changed since the database was created.
I found a solution to set the Database Initializer to null, but after this i keep getting the first error:
Invalid object name 'dbo.TableName2'
I also tried to set the the initializer to DropCreateDatabaseIfModelChanges and DropCreateDatabaseAlways, and these settings throw the exception:
Cannot drop database "DatbaseName" because it is currently in use
I think I already tried everything i found on the Web (there are many topics of this kind) but none helped me with it.
Dropping the Database didn't help, nor changing from Local File Database to SQL Server 2014 Exspress. The same exception is thrown. Any ideas?
Edit1:
Working context:
public class ProfilesContext : DbContext
{
public ProfilesContext() : base("DefaultConnection")
{
}
public DbSet<Profile> Profiles { get; set; }
public DbSet<PrevilegedContact> PrevilegedContacts { get; set; }
}
Failing context:
public class PlacesContext : DbContext
{
public PlacesContext()
: base("DefaultConnection")
{
}
public DbSet<Place> Places { get; set; }
public DbSet<Price> Prices { get; set; }
public DbSet<Photo> Photos { get; set; }
public DbSet<Comment> Comments { get; set; }
}
For what you are doing, it seems you have 2 options for your initializer. There is Migrations and there is DropCreateDatabaseIfModelChanges.
Migrations will give control over updating the database tables when your models change and allow you to preserve data. You can configure it to allow data loss or not. Very useful during development time if you already have test data in there.
DropCreateDatabaseIfModelChanges will simply drop the database each time you make model changes and recreate it with the new schemas.
You are getting the error message
Cannot drop database "DatbaseName" because it is currently in use
because you have more than likely browsed the table in your server explorer and have an open connection to the database. You can close the connection using the right click context menu in server explorer.
If you want a video overview on Migrations there is a free video by Scott Allen & Pluralsight. This is MVC4 but the Entity Framework section does cover Initalizers. If you want an updated one for MVC5 to include multiple Contexts etc, it does exist but you would need to take the Pluralsight free trial to get access to it.
I agree with James. Good point about checking Server Explorer. Right-click the database and choose Close Connection or at least check that there is a red X indicating the connection is closed. The link below is a great tutorial on the basics with Code First Migrations. The link is directly to the page within the tutorial that talks about making model changes and how to make EF happy again! http://www.asp.net/mvc/tutorials/mvc-5/introduction/adding-a-new-field. I prefer using Migrations. You would use the Package Manager Console and 1) Enable Migrations, 2) Add a migration, 3) Update the database. If in development, use LocalDb if possible, and use the Seed method in the Configuration class to prepopulate the database.
I tried to solve by myself, but... Looks like I need help from people.
I have Business Silverlight application with WCF RIA and EntityFramework. Access to Database I get via LinqToEntites.
Common loading data from database I making by this:
return DbContext.Customers
This code returns full Customers table from DataBase. But sometimes I do not need to show all data. Easy way is use linq filters in client side by next code:
public LoadInfo()
{
...
var LO1 = PublicDomainContext.Load(PublicDomainContext.GetCustomersQuery());
LO1.Completed += LO1Completed;
...
}
private void LO1Completed(object sender, EventArgs eventArgs)
{
...
DatatViewGrid.ItemsSource = null;
DatatViewGrid.ItemsSource = loadOperation.Entities.Where(c=>c ...filtering...);
//or PublicDomainContext.Customers.Where(c=>c ...filtering...)
...
}
However this way has very and very important flaw: all data passing from server to client side via DomainService may be viewed by applications like Fiddler. So I need to come up with another way.
Task: filter recieving data in server side and return this data.
Way #1: LinqToEntites has a beautiful projection method:
//MSDN Example
var query =
contacts.SelectMany(
contact => orders.Where(order =>
(contact.ContactID == order.Contact.ContactID)
&& order.TotalDue < totalDue)
.Select(order => new
{
ContactID = contact.ContactID,
LastName = contact.LastName,
FirstName = contact.FirstName,
OrderID = order.SalesOrderID,
Total = order.TotalDue
}));
But, unfortunately, DomainServices cannot return undefined types, so this way won't work.
Way #2: I found next solution - make separate DTO classes (DataTransferObject). I just read some samples and made on the server side next class:
[DataContract]
public partial class CustomerDTO
{
[DataMember]
public int ISN { get; set; }
[DataMember]
public string FIO { get; set; }
[DataMember]
public string Listeners { get; set; }
}
And based this class I made a row of methods which return filtered data:
[OperationContract]
public List<CustomerDTO> Customers_Common()
{
return DbContext.Customers....Select(c => new CustomerDTO { ISN = c.ISN, FIO = c.FIO, Listeners = c.Listeners }).ToList();
}
And this works fine, all good...
But, there is strange problem: running application locally does not affect any troubles, but after publishing project on the Web Site, DomainService returns per each method HTTP 500 Error ("Not Found" exception). Of course, I cannot even LogIn into my application. DomainService is dead. If I delete last class and new methods from application and republish - all works fine, but without speacial filtering...
The Question: what I do wrong, why Service is dying with new classes, or tell me another way to solve my trouble. Please.
U P D A T E :
Hey, finally I solved this!
There is an answer: Dynamic query with WCF RIA Services
Your best shot is to find out what is causing the error. For that, override the OnError method on the DomainService like this:
protected override void OnError(DomainServiceErrorInfo errorInfo)
{
/* Log the error info to a file. Don't forget inner exceptions.
*/
base.OnError(errorInfo);
}
This is useful, because only two exceptions will be passed to the client, so if there are a lot of nested inner exceptions, you should still be able to see what actually causes the error.
In addition, you can inspect the error by attaching the debugger to the browser instance you are opening the site with. In VS2010 this is done by doing [Debug] -> [Attach to Process] in the menu-bar.