Microsoft SQL Server Database

 1. master database 
the master database records all system-level information for the SQL Server system. It records all login accounts and system configuration settings. The master database is a database that records all other databases, including the location of the database files. The master database records the initialization information for SQL Server, and it always has a backup of the most recent master databases available. 

 2. tempdb database 
The tempdb database holds all temporary tables and temporary stored procedures. It also satisfies any other temporary storage requirements, such as storing SQL Server-generated worksheets. The tempdb database is a global resource, and all temporary tables and stored procedures for all users connected to the system are stored in the database. The tempdb database is recreated every time SQL Server starts, so the database is always clean when the system starts. Temporary tables and stored procedures are automatically dropped when the connection is dropped, and no connection is active when the system shuts down, so nothing in the tempdb database is saved from one session of SQL Server to another. 

by default, when SQL Server runs, the tempdb database automatically grows as needed. However, unlike other databases, it resets to its initial size each time the database engine is started. If the size defined for the tempdb database is small, then each time you restart SQL Server, the size of the tempdb database is automatically increased to the size required to support the workload, which may become part of the system processing load. To avoid this overhead, you can use ALTER database to increase the size of the tempdb database. 

 3. Model Database 
The model database is used as a template for all databases created on the system. When the CREATE DATABASE statement is issued, the first part of the new database is created by copying the contents of the model database, and the remainder is populated with empty pages. Because SQL Server creates the tempdb database each time it starts, the model database must always exist in the SQL Server system. 

 4. msdb database 
The msdb database is used by SQL Server Agent to dispatch alerts and jobs, and to record operators. 

5. Northwind Sample Database
The Northwind Traders sample database contains sales data for a fictitious company named Northwind Traders, which engages in the import and export trade of specialty foods from around the world

6. Pubs sample Database
The pubs sample database is modeled on a book publishing company and is used to demonstrate many of the options available in the Microsoft®sql Server™ database. The database and the tables in it are often used in the examples described in document content.

Microsoft SQL Server Database