Explain about SQL SERVER database Architecture?
Whenever we install SQL Server, it installs with 4 system Databases
- Master Database
- System Database
- Temp Database
- Model
Inaddition to above SQL Server allows users to create Database manually
Explain about SYSTEM DATA BASES?
- These are created along with installation by SQL Server
- These are mandatory in database
- These data bases are useful to perform adiministation related tasks
Master Database
- It records all login accounts and system configuration settings
- It records all system level information
Model
- It is termed as TEMPLATE database
- It is used as template for all the databases created on a system
Tempdb
- It consists of all temporary tables and stored procedures
- SQL server recreates everytime whenever we restarted
MSDB
This database is useful for:
- Backups
- Support Jobs
- Alerts
USER DEFINED DATABASES
- These are created by users
- These are for developers
How to create USER DEFINED DATABASES?
Database size depends two type files:
Data file consists of:
1)Primary Data file
2)Secondary Data file
Primary Data File
- It consists of extension .mdf
- MDF represents to MASTER DATA FILE
- Every database consists of at least one Primary datafile that keeps track of all files
Secondary Data File
- It consists of extension .ndf
- ndf represents to NEXT DATA FILE
- It holds all the data which doesn't fit into PRIMARY file
- If PRIMARY holds all the data, secondary file doesn't have
Log Files
- It consists of extension .ldf
- LDF represents to LOG DATABASE FILE STRUCTURE
- Every database should consists of at least one log file
Note: System defined databases are not possible to modify, where as user defined databases can modify.