Microsoft considers it the first choice for desktop applications. It is free to download. It is especially suitable for mobile and desktop development when you need a particularly streamlined relational database (accidental connection). Free download, development, deployment and distribution of embedded programs are streamlined. This version is a very good choice for many developers of shared software, because software users cannot feel the existence of the database at all. The database service is hidden in the process. Of course, its disadvantage is that it cannot use functions such as stored procedures. .