Entity Framework - Connection String - Best practice

Question

I develop an application using EF5 and I would like to know how to configure different connectionString (for example local and live). I know that all connectionsString are in app.config file:

<connectionStrings>
  <add name="MandatsEntitiesLocal" connectionString="metadata=res://*/MandatsModel.csdl|res://*/MandatsModel.ssdl|res://*/MandatsModel.msl;provider=System.Data.SqlClient;provider connection string='data source=&quot;localhost&quot;;initial catalog=&quot;UIVB Tests&quot;;user id=sa;password=***;MultipleActiveResultSets=True;App=EntityFramework'" providerName="System.Data.EntityClient" />
  <add name="MandatsEntities" connectionString="metadata=res://*/MandatsModel.csdl|res://*/MandatsModel.ssdl|res://*/MandatsModel.msl;provider=System.Data.SqlClient;provider connection string='data source=&quot;rmsi.net&quot;;initial catalog=&quot;UIVB Tests&quot;;user id=sa;password=***;MultipleActiveResultSets=True;App=EntityFramework'" providerName="System.Data.EntityClient" />
</connectionStrings>

I also know that I can switch between 2 different connection using DbContext constructor :

Partial Public Class MandatsEntities
Inherits DbContext

 Public Sub New()
    MyBase.New("name=MandatsEntities")
 End Sub

 Public Sub New(connectionName As String)
    MyBase.New(connectionName)
 End Sub

End Class

but I need to modify autogenerated class (and I think it's not recommanded)

So, to summarize if I have 10 contexts and 2 databases, I need to manage 20 connectionString !!! And I need to modify autogenerated class

Is there any method to do that properly? What is the best practice?

Typically different environment connection strings are handled via web.config transforms. When you build/deploy for another environment it will automatically transform the configs for you. Do you need access to all environments while developing? — Dismissile, Feb 28 '14 at 13:54
@Cooxkie There is similar concepts for app.config using post / pre-build events — Simon Belanger, Feb 28 '14 at 15:32

score 0 · Answer 1 · edited May 23 '17 at 12:09

0

Check out the Config Transform Nuget Package, it will allow you to perform Web.Config like transforms on a non-web project.

There is a walkthough of using this package in this another Stack Overflow question here.

edited May 23 '17 at 12:09

Community

1
1

answered Feb 28 '14 at 15:08

tom.dietrich

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Thank you for your help, even if it wasn't what I was looking for, you help me in my research ;-) ! – Cooxkie Mar 11 '14 at 16:55

score 0 · Answer 2 · answered Feb 28 '14 at 16:11

I don't know if this can directly help you, but I have had to handle different connection strings, for different entities before.

What I do is implement the logic in the repository.

If you want a context intialized with different connection strings, depending on the entity the repository has been initialized with, you can do something like:

//'Customers' and 'Orders' are in a different database than 'Products' and 'Vendors'...
private string[] _EntitiesGroup1 = { typeof(Customers).Name, typeof(Orders).Name };
private string[] _EntitiesGroup2 = { typeof(Products).Name, typeof(Vendors).Name };

In your repository constructor, you can do something like:

public Repository()
{
    if (Array.Exists(_EntitiesGroup1 , x => x == typeof(T).Name))
        _context = new Entities1();

    if (Array.Exists(_EntitiesGroup2 , x => x == typeof(T).Name))
        _context = new Entities2();


    _objectSet = _context.CreateObjectSet<T>();

}

Hope this somewhat helps.

Thank you for your help, even if it wasn't what I was looking for, you help me in my research ;-) ! — Cooxkie, Mar 11 '14 at 16:54

score 0 · Accepted Answer · edited May 23 '17 at 10:31

OK I found a solution and need to make some concession ;-) !

First I modified constructor of every Entities. I added new constructor with string parameter :

    'constructor auto-generated
    Public Sub New()
     MyBase.New("name=ViticulteurEntities")
    End Sub

    'constructor added by me
    Public Sub New(connectionName As String)
     MyBase.New(connectionName)
    End Sub

Second I created my own connection string :

viticulteurConnectionString = New System.Data.EntityClient.EntityConnectionStringBuilder() _
        With {
            .Metadata = "res://*/MandatsModel.csdl|res://*/MandatsModel.ssdl|res://*/MandatsModel.msl", _
            .Provider = "System.Data.SqlClient", _
            .ProviderConnectionString = "data source=rmsi.net;;initial catalog=&quot;UIVB Tests&quot;;user id=sa;password=***" _
             }.ConnectionString

Third, I used my own constructor with my own connection string ;-)

 Dim viticulteurContext As ViticulteurEntities
 .
 .
 .
 viticulteurContext = New ViticulteurEntities(viticulteurConnectionString)

sources :

Thanks all !

Entity Framework - Connection String - Best practice

3 Answers3