Nao entendi pq pelo que vejo vc pode setar de 2 formas:
PRIMEIRA
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework">
<parameters>
<parameter value="Data Source=(localdb)\v11.0; Integrated Security=True; MultipleActiveResultSets=True" />
</parameters>
</defaultConnectionFactory>
</entityFramework>
SEGUNDA
<connectionStrings>
<add name="BlogContext"
connectionString="metadata=res://*/BlogModel.csdl|
res://*/BlogModel.ssdl|
res://*/BlogModel.msl;
provider=System.Data.SqlClient;
provider connection string=
"data source=.\SQLEXPRESS;
initial catalog=Blogging;
integrated security=True;
multipleactiveresultsets=True;""
providerName="System.Data.EntityClient" />
</connectionStrings>