Entity Framework 6 - Knowledge Base (KB)

Where is |DataDirectory| defined?

This is a follow up question of ...Where is that file on my system?...Tons of questions and answers all over SO and the internet but I can't find any that gives an answer to this specific question....All is default but I can't find the file itself,...IT'S...

When to use .mdf and when .sdf?

After seeing a lot of things in the internet I haven't found any explanation between the two file types: ....mdf... and ....sdf........sdf... would be a compact version of SQL Server (....mdf...) I believe. Still they appear utterly different....Have foll...