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| Architecture of Database |
Architecture Of Database
In this diagram we can see architecture of database which includes Database,Physical File,Logical Files
Database
Database is a combination of logical files and physical files
Physical Files
- Physical files are divided into three types control file,redo file and database file.
- These physical files are stored in hard disk.
- These Physical files are useful in recover
- Can access all files regardless of database up or down
- These files are operating system level files
- Data Files-- These contains organizaions original data
- Redo Log File--These holds the information that a record of change made to the database,and enables recovery when failures occur
- Control File--These are used to syncronize all database activities
- Logical files are the files which are created at database level.
- These files can access only when the database is up and running
- Logical file are of different types as follows
------Tables
------Sequences
------Package
- Starting an oracledb is know as starting the instance
- Only after instance gets started user can login,established sessions and can perform sequeal operations
- when a client establishes a session with the server oracle creates a user process on the client and a server process on the server(In a dedicated environment)
- Only Database Administrator can start or stop database
Roles of Database Administrator
- Gathering system resources
- Installing RDBMS
- Creation of databse
- Table space Managment
- User Managment
- Backup and Recovery
- Performance Tuning
