Azure SQL Server – Entity Framework Connection

By default when Entity framework is added to a project, a file “App.config” is created if it doesn’t exists yet.
( “Web.config” in web applications).
A default connection factory that will connect to a local database is added in this file:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
 
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
 
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.1" />
  </startup>
 
  <!-- By default, when no connection string is specified use the local database.-->
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
 
</configuration>
  

This factory will be used when no connection string for the specified context is found. But let clarity how EF try to find the connection string to use…

Which connection string will EF use?

To connect to the database we use a context that extend DbContext.

By default if we don’t call a DbContext base constructor, E.F. will look for a connection string name using the name of our defined context.

namespace CodeFirstAzureTest.Data
{
    public class FoodContext : DbContext
    {
        public DbSet<Food> Foods { getset; }
        public DbSet<Recipe> Recipes { getset; }
        public DbSet<FridgeEntry> Fridge { getset; }
 
    }
}

It is possible to specify the name of the connection string or the complete connection string calling the base constructor:

using System.Data.Entity;
using CodeFirstAzureTest.Data.Entities;
 
namespace CodeFirstAzureTest.Data
{
    public class FoodContext : DbContext
    {
        // NOTE: Call base constructor to specify the connection string name
        public FoodContext() : base("name=MyFood") { }
 
        public DbSet<Food> Foods { getset; }
        public DbSet<Recipe> Recipes { getset; }
        public DbSet<FridgeEntry> Fridge { getset; }
 
    }
}

When no connection string is defined, if a defaultConnectionFactory is defined, EF will use it to create a connection string using the name of the connection string he needs.

e.g. If we don’t specify the connection string name in our context and EF cannot find any connection string the factory will create one using exactly this name. This is why by default the database created locally had this name in my previous post.

Connect EF to Windows Azure

To connect to a Windows Azure we need to do the following steps:

1. Create a SQL Database in Azure

2. Add a Firewall rule

image

3. Copy the ADO.NET connection string from “View SQL Database connection strings”

image

4. Add the connection string to the App.config file

If we run now our application the changes that we apply to our DbContext will be persisted on Azure when changes are saved. This my “App.config”.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
 
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
 
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.1" />
  </startup>
 
  <!--Azure MyFood database, connection string-->
  <connectionStrings>
    <add name="MyFood"
     providerName="System.Data.SqlClient"
     connectionString="Data Source=i608rt1tak.database.windows.net;Initial Catalog=MyFood;Integrated Security=False;User ID=ravened;Password=thisismypass;Connect Timeout=60;Encrypt=False;TrustServerCertificate=False" />
  </connectionStrings>
 
  <!-- By default, when no connection string is specified use the local database.-->
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
 
</configuration>
  

After we run the sample application to create the database and add some sample data we can see the result in Visual Studio using the SQL Server Object Explorer and also using the Management Portal of Windows Azure:

image

Using the management portal we can not only see the data of our tables but also:

Edit the table name and columns:

image

View Indexes and Keys:

image

View relationships:

image

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