1. Database administration
Duties of the DBA
Installing and upgrading server and utilities
Physical database design
Starting up and shutting down the database server
Creating user accounts and control access
Monitoring data storage space
Database application development
Backup and recovery operations
Shared resources: CPU, memory, storage
Multiuser
Multitasking
Database: organized collection of data in data files
Instance: set of processes and memory storage areas
background processes
shared memory area
data storage area

2. Instances Background processes
Serving user requests: connecting to DB, browse, insert, update, delete data
Writing data to datafiles: first to shared memory and then to database
Writing transactions to log files: recovery from system failures
Monitoring database functions: disk space utilization
Shared memory areas: part of main memory used by the DBMS
software code area: store code to be executed
SGA (System Global Area): store user transactions
database buffer cache
redo log buffer
shared SQL areas
data dictionary cache
PGA (Program Global Area): information about the processes
Sort areas: used for sorting records (ORDER BY clause in SQL)

3. Disk data storage areas
datafiles: where the data is stored
tablespaces
SYSTEM: user accounts and passwords
ROLLBACK_DATA: to rollback transactions
this information is stored in rollback segments
TEMPORARY_DATA: to hold data too large to store in main memory
extents: stores data for a designated table
INITIAL_EXTENT: amount of disk space set aside when a table is first
created
NEXT_EXTENT: amount of disk space to be added once
INITIAL_EXTENT is full
MIN_EXTENT: minimum number of extents to be allocated to a table
in the tablespace
MAX_EXTENT: maximum number of extents to be allocated to a
table in the tablespace