Data Files: These are the primary files used to store data in MSSQL. They are divided into two types: Primary Data Files and Secondary Data Files. Transaction Log Files: These files store all the changes made to the data in the database. They are used to ensure that all changes are properly logged and can be restored in case of a system failure. Full-Text Catalog Files: These files are used to store full-text search data for text columns in MSSQL databases. Backup Files: These files are used to make copies of the database in case of a system failure. System Database Files: These files store system-level information such as user accounts, roles, and permissions.