[c#] how to open *.sdf files?

I used to open sdf (sqlCE) files with visual-studio? or sql-server? I really don't remember. Now I can't open this sdf file. With what program do I need to open it?

If you simply need to view the table and run queries on it you can use this third party sdf viewer. It is a lightweight viewer that has all the basic functionalities and is ready to use after install.

and ofcourse, its Free.

Try LINQPad, it works for SQL Server, MySQL, SQLite and also SDF (SQL CE 4.0). Best of all it's free!

Steps with version 4.35.1:

1. click 'Add Connection'

2. Click Next with 'Build data context automatically' and 'Default(LINQ to SQL)' selected.

3. Under 'Provider' choose 'SQL CE 4.0'.

4. Under 'Database' with 'Attach database file' selected, choose 'Browse' to select your .sdf file.

5. Click 'OK'.

6. Voila! It should show the tables in .sdf and be able to query it via right clicking the table or writing LINQ code in your favorite .NET language or even SQL. How cool is that?

In addition to the methods described by @ctacke, you can also open SQL Server Compact Edition databases with SQL Server Management Studio. You'll need SQL Server 2008 to open SQL CE 3.5 databases.

You can use SQL Compact Query Analyzer

http://sqlcequery.codeplex.com/

SQL Compact Query Analyzer is really snappy. 3 MB download, requires an install but really snappy and works.

It can be opened using Visual Studio 2012.Follow the below path in VS after opening the project. View->Server Explorer->