An SDF file contains a compact relational database saved in the SQL Server Compact (SQL CE) format, which is developed by Microsoft. It is designed for applications that run on mobile devices and desktops and contains the complete database contents, which may be up to 4GB in size.

You will most likely only encounter SQL CE SDF files if you are a database architect or developer. You can open an SDF file with several programs, including Microsoft Visual Studio and LINQPad. To open an SDF file with Visual Studio, select View → Server Explorer → Data Connections → Add Connection..., change the data source to "Microsoft SQL Server Compact," click Browse..., and select the SDF file. To open an SDF file with LINQPad, follow these steps: Click "Add connection" in the top-left pane Select "Build data context automatically," choose "LINQ to SQL," and click Next >. Select "SQL CE 4.0 (auto-install)" in the Provider section. Click "Attach database file" in the Database section, click "Browse," and choose the SDF file. NOTE: Previous versions of SQL Server Compact were distributed as SQL Server for Windows CE and SQL Server Mobile Edition.

Standard database format used for storing data in a structured format; uses fields of fixed lengths to store values; can be imported and exported by various database and data analysis programs; commonly used for transferring data between different programs.

Chemical data file created in the Structure Data File (SDF) format, which was developed by Molecular Design Limited (MDL); saved in plain text and contains chemical structure records; used as a standard exchange format for chemicals information.

Molecular Design Limited was renamed to MDL Information Systems and then later was acquired by Symyx Technologies, the organization that now maintains the SDF format.

Map file used by World in Conflict, a real-time tactics war simulation game; stores the terrain, spawn points, item locations, and other map details; used for multiplayer gameplay.

Custom maps can be created using WicEd, the World in Conflict map editor.