How to use pre-designed SQLite in UWP project?

I can create a new Database and use it but I don't know how to copy database file from project. I use from SQLite.Net-PCL nuget package.

For how to access an exist file, there are two locations that all apps can access. Details please reference the file-access-permissions.

One is Application install directory. As @Henk Holterman said, you can import your existed database file into your project by right-click one folder and select Add->Existing item to add your database file to the project. Pay attention the file's Build action property need to be set to content. Details please see the following picture.

Suppose you already had a database file Sun.db added to the Assets folder, and now you can connect to it by the following code( use the SQLite.Net-PCL Nuget Package).

  path = Path.Combine(Windows.ApplicationModel.Package.Current.InstalledLocation.Path, @"Assets\Sun.db");  using (SQLite.Net.SQLiteConnection conn = new SQLite.Net.SQLiteConnection(new SQLite.Net.Platform.WinRT.SQLitePlatformWinRT(), path))  {  }

But this folder is read only. Another location is Application data locations which can read/write. You can copy the database file from install directory to the application data directory for using. The following code example is for connecting a database file that in the local folder.

  StorageFile file;  try  {      file = await Windows.Storage.ApplicationData.Current.LocalFolder.GetFileAsync("Sun.db");  }  catch  {      StorageFile Importedfile = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///Assets/Sun.db"));      file = await Importedfile.CopyAsync(Windows.Storage.ApplicationData.Current.LocalFolder);  }  path = file.Path;  using (SQLite.Net.SQLiteConnection conn = new SQLite.Net.SQLiteConnection(new SQLite.Net.Platform.WinRT.SQLitePlatformWinRT(), path))  {      conn.CreateTable<User>();  }