为什么连接字符串不能用于EF迁移?

I have created a database for use with a NuGet Gallery implementation. I can see the database in sql manager 2012 and I can access it from a test program I wrote, using my connection string. However, when I try to run the Update-Database command in the package manager console, to have EF set up the database, I keep getting the error: "The server was not found or was not accessible.".I have created a database for use with a NuGet