Sql server database files

Sql server database have three type of file 

1) Primary data files
2) Secondary data files
3) log files

What are primary data files?

The primary data file is the starting point of the database
 primary data file also called .MDF.

What are secondary data files?

Secondary data files is optional data file. IT can be used for spreading data on the different storage media .
Secondary data files also called .NDF

What is log files?

The log files contain log information of the database  that is used to recover the data.

• Log file also called .ldf file
• Every database have at least one  log file .

• .MDF – primary database file
• .NDF- secondary data files
• .LDF- log file.