Connection strings in Entity Framework

Question

I am referencing 2 databases in ASP.NET using Entity Framework.

In my web.config file, I can see the connection strings for the 2 databases:

<connectionStrings>
    <add name="RContext" 
         connectionString="metadata=res://*/Models.RModel.csdl|res://*/Models.RModel.ssdl|res://*/Models.RModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=localhost\SQLEXPRESS;initial catalog=RStreamline;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" 
         providerName="System.Data.EntityClient" />
    <add name="CEntities" 
         connectionString="metadata=res://*/Models.CModel.csdl|res://*/Models.CModel.ssdl|res://*/Models.CModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=localhost\SQLEXPRESS;initial catalog=RStreamline;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" 
         providerName="System.Data.EntityClient" />
</connectionStrings>

Can I somehow implement alternate connection strings where the datasource refers to the prod server for the release?

Answer 1

This is typically handled with web.config transforms.

In your project you would have:

• web.config
• web.Release.config

For example in your web.Release.config transform you would have something like this:

<?xml version="1.0"?>
<configuration xmlns:xdt="https://schemas.microsoft.com/XML-Document-Transform">
  <connectionStrings>
    <add name="RContext" 
      connectionString="RContext-Prod-Connection-String" 
      xdt:Transform="SetAttributes" xdt:Locator="Match(name)"/>
    <add name="CEntities" 
      connectionString="CEntities-Prod-Connection-String" 
      xdt:Transform="SetAttributes" xdt:Locator="Match(name)"/>
  </connectionStrings>
</configuration>

You'll notice the xdt:Transform="SetAttributes" xdt:Locator="Match(name)" bit, which says, in the main web.config find the connectionString by name and replace its attributes with the ones defined here.

This will automatically happen when you publish the application.