Master It contains system catalogs that keep information about disk space, file allocations, usage, system wide configuration settings, login accounts, the existence of other database, and the existence of other SQL Servers (for distributed operations).
Model It is a simply a template database. Every time you create a new database, SQL Server makes a copy of model to form the basis of the new database.
Tempdb Temporary database, tempdb, is a workspace. SQL Server’s tempdb database is unique among all other databases because it is recreated not recovered every time SQL Server is started.
Msdb This database is used by the SQL Server Agent Service, which performs scheduled activities such as backups and replication tasks.
Database Files: A database file is nothing more than an operating system file. SQL Server 2000 allows the following three types of database files:
·Primary data files (.mdf)
·Secondary data files (.ndf)
·Log files (.ldf)
When we create a new user database, SQL Server copies the model database (includes 19 system tables and 2 system views (for backward compatibility)). A new user database must be 1MB or greater in size.
We can create a new database using the following command: CREATE DATABASE newdb
Types of Backups:
* Full Backup
* Differential Backup
* Log Backup
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