what is sql server compact edition database file
SQL Server Compact SQL CE databases reside in a single .sdf file,[12] which can be up to 4 GB in size.[4] The .sdf file can be encrypted with 128-bit encryption for data security.[12] SQL CE runtime mediates concurrent multi-user access to the .sdf file. The .sdf file can simply be copied to the destination system for deployment, or be deployed through ClickOnce. SQL CE runtime has support for DataDirectories.[6] Applications using an SQL CE database need not specify the entire path to an .sdf file in the ADO.NET connection string, rather it can be specified as |DataDirectory|\<database_name>.sdf, defining the data directory (where the .sdf database file resides) being defined in the assembly manifest for the application.[citation needed]