The LDF - SQL Server Transaction Log File is a log file designed and created by Microsoft for the purpose of tracking and recovering data that can be lost during hardware failure on desktops and laptops. The LDF - SQL Server Transaction Log File is a RDBMS (Relational Database Management System) that provides the capability to manage hardware events in a manner that allows the program to locate, track and recover valuable data and files that may be lost due to equipment failure. Something as simple as a powerful failure can cause you to lose files and data, sometimes permanently. The LDF creates a scenario in which recovery is possible.
The LDF allows the database to execute a log of the user’s most recent actions so that when there is an unexpected shutdown the programs can retrieve the data that was at risk during the shutdown. The logs are transaction logs; designed to track actions in sequential order. This log gives the user the capability of restoring the database to its exact status before system failure occurred.
Once the database creates a checkpoint, the stable state of the log file and database, the transaction log can be truncated. Once this has been done the system can safely delete all transactions that have been logged up to the created checkpoint with no chance of losing data.