SQL Server database files

[UncleRonin]

Just a question on how SQL Server actually works. I know that the actual datbase information is stored in the .mdf file but what is the .ldf used for? It's some form of log file i guess but what information does it actually keep? just a record of transactions? Is it used for rolling back errors or other things like that?

The real question is that if the .ldf is not available will the database still function correctly? I'm using a VB.NET app and doing existential checks so if a database file is missing i disable the associated function. If the .ldf is missing should i disable the associated function?

If anyone can help me I'd really appreciate it

 

[JohnH]

The ldf file is the transaction log of the database and is required for operation ("critical component of the database").
See MSDN "Transaction Log Fundamentals" http://msdn2.microsoft.com/en-us/ms190653.aspx