Data structures and transaction logging

We can think about a database as of physical database structure consisting of tables and indexes. However, this is just a human point of view. From the SQL Server's perspective, a database is a set of precisely structured files described in a form of metadata also saved in database structures.

A conceptual imagination of how every database works is very helpful when the database has to be backed up correctly.

How data is stored

Every database on SQL Server must have at least two files:

• The primary data file with the usual suffix, mdf
• The transaction log file with the usual suffix, ldf

For lots of databases, this minimal set of files is not enough. When the database contains big...