This document provides an overview of Oracle Database. It discusses database concepts like the entity-relationship model, normalization, and SQL. It describes Oracle architecture including memory structures like the shared pool and database buffer cache. It outlines Oracle processes such as the database writer and log writer. It also covers storage structures, both physical (data files, segments, extents, blocks) and logical (tablespaces, tables, indexes).

1. Overview of Oracle Database
Lee, JeongKyu (jelee@bridgeport.edu)

2. Part 1. Introduction to Database System
 Introduction to Database
 History of RDBMS
 Entity-Relationship Modeling
 Database Language

3. Introduction to Database
 File-Based Approach
 Each program defines and manages its own data
 Limitation
 Separation and isolation of data
 Duplication of data
 Data dependence
 Incompatibility of files
 Fixed queries/proliferation of application program
 Database Approach
 A shared collection of logically related data, designed
to meet the information needs of an organization

4.  Database Management System(DBMS)
 A software system that enables users to define, create and
maintain the database and provides controlled access to
database
 DDL
 DML : procedural, non-procedural
 Control : security, integrity, concurrency control,
recovery control, user-accessible catalog
 Components of the DBMS Environment
 Hardware - Software - Data - Procedures - People

5.  Advantages of DBMS
- Control of data redundancy - Economy of scale
- Data consistency - Balance of conflicting requirements
- More information from the same amount of data
- Sharing of data - Improved data accessibility and
responsiveness
- Improved data integrity - Increased productivity
- Improved security - Improved maintenance through data
independence
- Enforcement of standards - Increased concurrency
- Improved backup and recovery services
 Disadvantages of DBMS
- Complexity, Size, Cost of DBMSs, Additional H/W costs
- Cost of conversion, Performance, Higher impact of a failure

6.  Three-Level Database Architecture
 External Level
The users’ view of the database
 Conceptual Level
The community view of the database
 Internal Level
The physical representation of the database on the computer

7.  Functions of a DBMS
1. Data storage, retrieval, and update
2. A user-accessible catalog
3. Transaction support
4. Concurrency control services
5. Recovery services
6. Authorization services
7. Support for data communication
8. Integrity services
9. Services to promote data independence
10. Utility services

8.  Components of a DBMS
Programmers Users DBA
Application Database
Queries
Programs Schema
DML Query DDL DBMS
preprocessor processor compiler
Program Database Dictionary
object code manager manager
Access File
methods manager
System Database and
buffers system catalog

9.  Components of Database Manager
Authorization
control
Integrity Command Query
checker processor optimizer
Transaction
Scheduler
manager
Data
Buffer Recovery
Manager
manager manager

10. History of RDBMS
 History of DBMS
 1960s - Apollo moon-landing project, GUAM
 mid 1960s - IMS by IBM (hierarchical DBMS)
 mid 1960s - IDS by GE (network DBMS)
 1965 - CODASYL(Conference on Data SYStems
Language)
 1967 -DBTG(Data Base Task Group)
 1970 - E.F.Codd of the IBM Research Lab.
 Late 1970s - System R project at IBM
 1980s - commercial relational DBMS(DB2, Oracle,
Informix..)
 Now - OODBMS, ORDBMS

11.  Terminology
 Relation : a relation is a table with columns and rows
 Attribute : an attribute is a named column of a relation
 Domain : a domain is the set of allowable values for
one or more attributes
 Tuple : a tuple is a row of a relation
 Degree : the degree of a relation is the number of
attributes it contrains
 Cardinality : the cardinality of a relation is the number
of tuples it contains
 Relational database : a collection of normalized
relation

12.  Properties of Relations
 The relation has a name that is distinct from all other
relation names
 Each cell of the relation contains exactly on atomic
value
 Each attribute has a distinct name
 The values of an attribute are all from the same domain
 The order of attributes has no significance
 Each tuple is distinct; there are no duplicate tuples
 The order of tuples has no significance, theoretically

13.  When is a DBMS Relational?
 Foundational rules
Rule 0 : Foundational rule Rule 12 : Nonsubversion rule
 Structural rules
Rule 1 : Information representation Rule 6 : View updateing
 Integrity rules
Rule 3 : Systematic treatment of null values Rule 10 : Integrity independance
 Data manipulation rules
Rule2 : Guaranteed access Rule 4 : Dynamic online catalog based on the
relational model
Rule5 : Comprehensive data sublanguage Rule7 : High-level insert, update, delete
 Data independence rules
Rule8 : Physical data independence Rule 9 : Logical data independence
Rule11 : Distribution independence

14. Entity-Relationship Modeling
 Concepts of the E-R Modeling
 Entity Types
An object or concept that is identified by the enterprise as having an
independent existence
 Attributes
A property of an entity or a relationship type
 Relationship Types
A meaningful association among entity types

15.  Normalization
 A technique for producing a set of relations with desirable
properties, given the data requirements of an enterprise
 UNF is a table that contains one or more repeating groups
 1NF is a relation in which the intersection of each row and column contains one
and only one value
 2NF is a relation that is in 1NF and every non-primary-key attribute is fully
functionally dependent on the primary key.
 3NF is a relation that is in 1NF, 2NF in which no non-primary-key attribute is
transitively dependent on the primary key
 BCNF is a relation in which every determinant is a candidate key
 4NF is a relation that is in BCNF and contains no trivial multi-valued
dependency
 5NF is a relation that contains no join dependency

16.  Conceptual Database Design
 The process of constructing a model of the information
used in an enterprise, independent of all physical
considerations
 Logical Database Design
 The process of constructing a model of the information
used in an enterprise based on a specific data model,
but independent of a particular DBMS and other
physical considerations.
 Physical Database Design
 The process of producing a description of the
implementation of the database on secondary storage;
it describes the storage structures and access
methods used to archieve efficient access to the data

17. Database Language
 SQL
 1974 - SEQUEL by D.Chamberlin (IBM)
 1975 - SQUARE by Boyce (System R project)
 1976 - SEQUEL/2 (SQL) by Chamberlin and Boyce)
 late 1970 - SQL(Oracle), QUEL(Ingres)
 1982 - Relational Database Language(RDL) : ANSI
 1987 - ISO standard
 1989 - Integrity Enhancement Feature (ISO)
 1992 - SQL2(SQL92) : ISO

18.  DML
 SELECT
 INSERT
 UPDATE
 DELETE
 DDL
 CREATE(DROP) SCHEMA
 CREATE(ALTER, DROP) DOMAIN
 CREATE(ALTER, DROP) TABLE
 CREATE(DROP) VIEW
 CREATE(DROP) INDEX

19.  Advanced SQL
 View
 Integrity Enhancement Feature
 Primary key
 Unique
 Foreign key
 Access Control
 Embedded SQL
 Host Language Variables
 Application Programming Interface
 Dynamic SQL

20. Part 2. Understanding Oracle Database
 Overview of oracle Database Architecture
 Memory Structure
 Process Structure
 Storage Structure
 New Features

21. Overview of Oracle Architecture
PMON SMON RECO D000 S000 P000 * Total SGA Size :
1700 Mbyte
* Fixed Size :
Redo Log 70 Kbyte
SGA Buffer
Shared SQL Area Database Buffer Cashe
* Variavle Size :
490 MByte
TL-812
4,000,000 KByte 1,200,000 KByte 2,100 KByte
DBW0 CKPT LGWR
Server
Data File
Raw Device ARCH
USER
Archive Log Mode(50M)

22. Memory Structure : Shared Pool
Shared Pool  Shared Pool Contents
- Text of the SQL or PL/SQL statement
Library Cache Dictionary
Cache - Parsed form of the SQL or PL/SQL statement
- Execution plan for the SQL or PL/SQL
Shared
statements
SQL Area
- Data dictionary cache containing rows of data
dictionary information
Control Structures
for example:  Library Cache
PL/SQL Procedures - shared SQL area
Character Set
and Package Conversion - private SQL area
Memory
Network Security - PL/SQL procedures and package
Attributes
Control Structures - control structures : lock and library cache handles
for examples; and so on ..
 Dictionary Cache
Locks
Library - names of all tables and views in the database
Cache handles Reusable
and so on ... Runtime - names and datatypes of columns in database tables
Memory - privileges of all Oracle users
 SHARED_POOL_SIZE

23. Memory Structure :Database Buffer Cache
 Database Buffer Cache holds copies of data blocks read from disk
 All users concurrently connected to the system share access to the buffer cache
 Dirty List
 LRU List
 Size = DB_BLOCK_SIZE * DB_BLOCK_BUFFERS
SGA Database Buffer Cache
Shared Pool
Shared SQL Area

24. Memory Structure :Redo Log Buffer
 Circular buffer containing information about changes made to the database
 save it redo entry
 Redo Entries is used when Database Recovery
 DBWR write contents of Redo Log Buffer to Online Redo Log
 LOG_BUFFER
change vector #1
redo record
change vector #1
change vector #1

25. Oracle Processes
SNPn SMON PMON RECO LCK0
Pnnn
SGA
Database Buffer Cache Redo Log
Buffer
Offline
Storage
Device
Dedicated
Snnn Server
Process
DBWR LGWR ARCH
Dnnn
User
Process CKPT
Control
Files
Users Redo Log
Data Files
Files

26. Background Process
 DBWR (Database Writer)
- write all dirty buffers to datafiles
- Use a LRU algorithm to keep most recently used blocks in memory
- Defers write for I/O optimization
 dirty list reaches a threshold length
 A process scnas a specifed number of buffer in the LRU without finding free buffer
 A time-out occurs
 DBWR checkpoint occurs
 LGWR (Log Writer)
- writes redo log entries to disk
 Commit occurs
 The redo log buffers pool becomes one-third full
 DBWR completes cleaning the buffer blocks at a checkpoint
 LGWR time-out
- A commit confirmation is not issued until the tx has been recorded in the rego
log file

27. Cont’d
 PMON (Process Monitor)
- Cleans up abnormally terminated connection
- Rolls back uncommited transactions
- Releases locks held by a terminated process
- Frees SGA resources allocated to the failed processes
- Database maintenance
 SMON (System Monitor)
- Performs automatic instance recovery
- Reclaims space used by temporary segments no longer in use
- Merges contiguous area of free space in the datafile

28. Cont’d
 CKPT (Check Point)
- is enabled by setting the parameter CHECKPOINT_PROCESS=TRUE
- If enabled, take over LGWR’s task of updating files at a checkpoint
- Updates header of datafiles and control files at the end of checkpoint
- More frequent checkpoint reduce recovery time from instance failure
- CKPT improve the performance of database with many database files
 ARCH (Archiver)
- Copies redo log files to tape or disk for media failure
- Operates only when a log switch occurs
- Is optional and is only needed when in ARCHIVELOG mode
- May write to a tape drive or to a disk
 LCKn (Lock), Dnnn (Dispatcher), Snnn (Server),
RECO (Recover), Pnnn(Parallel), SNPn(Job Queue),
QMNn(Queue Monitor),

29. Server/User Process
 User Processes
- A user process is used when a user runs an application program
- Runs the tool/application and is considered the client
- Passes SQL to the server process and receives the results
 Server Processes
- A server process must place the data in the database buffer cache
- Parce and execute SQL statements
- Read data blocks from disk into the shred database buffers of the SGA
- Return the results of SQL statements to the user process
 Parse : check syntax, security access, object resolution, optimization
 Execute : applies the parse tree to the data, perform a physical read and
change
 Fetch : Passes data to the user (only SELECT)

30. Oracle Files
 Datafile
 Redo Log Files
 Control Files
 Parameter File
 Archive File
 Log File (alert*.log, sqlnet.log, listener.log...)
 Trace File

31. Storage Architecture
 Physical storage structures
 Data files
 Segments
 Extents
 Blocks
 Logical storage structures
 Tablespaces
 Tables / Clusters / Indexes
 Rows
 Columns

32. Physical Storage Architecture
 Relationship among Segments, Extents, and Blocks
Segment
96K
Extent Extent
24K 72K 2K
2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
2K 2K 2K 2K
Database Blocks

33. Logical Storage Architecture
 Relationship between tablespaces and datafiles
Database
System Tablespace USER Tablespace
DATA1.ORA DATA2.ORA
DATA3.ORA

34. Cont’d
 Objects stored in tablespaces
Tablespace (one or more datafiles)
Table Table INDEX
INDEX INDEX INDEX INDEX
INDEX INDEX
INDEX Table
INDEX INDEX
Database Files Objects
(Physical structures associated (stored in tablespace may
with only one tablespace) span serveral datafiles)

35. Block
Header General Block Information
Table Dictionary (Block add, Segment type)
Row Dictionary 85 ~ 100 bytes
Free Space Table info in Cluster
Row info in Block
(2 byte per row)
Row Data
using when New Row
Insert or Update
(pctfree, pctused)
Table or Index Data

36. PCTFREE / PCTUSED
PCTFREE PCTUSED
20% Free space
61% Free space
PCTFREE = 20 PCTUSED = 40
 Insert new row until 80%  Can insert new row when below 60%
 When Usage is below 40% (61% Free
 20% use when Update space), block is listed in FREELIST

37. Extent
A set of contiguous database blocks within a datafile.
 Extent are allocated when.
- The segment is created (INITIAL EXTENT)
- The segments grows (NEXT EXTENT)
- The table is altered to allocate extents.
 Extent are de-allocated when the
- The segment is dropped and truncated.
- The segment is larger than optimal and contains free extents
(for rollback segments only)
 Each segment is created with at least on extend( initial extent )
( Rollback segment : 2)
 ALTER TABLE table_name DEALLOCATE UNUSED

38. Segment
 a set of one or more extents that contains all the data for a specific type of logical storage
structure within a tablespace
 Data Segment
- A collection of extents that holds all of the data for a table or a cluster
 Index Segment
- A collection of extents that holds all of the index data for search optimization on large tables
and clusters
 Rollback Segment
- A collection of extents that holds rollback data for rollback, read-consistency, or recovery
 Temporary segment
- A collection of extents that holds data belonging to temporary tables created during a sort
operation
 Bootstrap segment
- An extent that contains dictionary definitions for dictionary tables to be loaded when the
database is opened.

39. Oracle8 New Feature
VLDB, Warehouse OLTP
Parallel DML Advanced Queuing
Parallel Index Scans XA rewrite
Star Query Optimization Memory reduction
Partitioning Serially reusable memory
Parallel Backup/Recovery New OCI Interface
Incremental Backup Improve Function Performance
Point-in-time Recovery
Objects Network Computing
Object Relational Database Simple User Integration
Object Type Simple Maintenance
Object View Simple Development

40. Oracle8i New Features
Data Warehousing OLTP
 Summary management  Publish and subscribe capabilities
 Analytic function  Database event trigger
 Hash and Composite Paritioning  Single table hash cluster
 Resource Management  Object type column in partition table
 Transportable tablespace  Partitioned index-organized table
 Functional index, virtual column  Stable optimizer execution plans
Application Development Security
 Oracle Jserver, VM in Database  Virtual Private Database
 Java stored procedure, function..  LDAP integration
 SQLJ: embedded SQL in Java  N-tier authentication/authorization
 WebDB  SSL and X.509v3, RAIDUS support
 Data encrypt, decrypt

41. Oracle 9i - The eBusiness Platform
 Oracle9i continues Oracle8i's focus on the Internet by providing a series of
specific capabilities and product bundles targeted at eBusiness environments. In
addition, Oracle9i continues to add features and capabilities that extends existing
investment in mission-critical infrastructure. Oracle9i has been designed with
focus on certain key development areas.
Key Infrastructure Area Key Application Area
 Availability  Internet Contents Management
 Scalability and Performance  B2B and B2C eBusiness
 Security  Packaged Application
 Development Platform  Business Intelligence
 Manageability
 Windows2000 Integration

42. Oracle Client/Server Architecture
NETWORK
Client Server b
Application
Client/Server Server/Server
Server A
 Benefit of Client/Server Component
- Database S/W work on Server - Only Server upgrade to increase size
- Minimize network resource - Minimize Client H/W spec
- concurrency, consistency, transparency - concurrency, consistency, transparency

43. SQL*Net
 What is SQL*Net?
- Oracle’s Client/Server middleware product
- transparent connection from client tool to DB ( from on DB to another )
- works across multiple network protocol and operation system
 What is TNS?
- Transparent Network Substrate
- Oracle’s Network applications to access the underlying network protocols transparently
- TNS-based application, Oracle Protocol Adapters, Network software like TCP/IP
 Configuration File
- TNSNAME.ORA ( Client )
- TNSNAV.ORA ( Client )
- SQLNET.ORA ( Client, Server )
- LISTENER.ORA ( Server )

44. SQL*Net Configuration
 TNSNAME.ORA  LISTENER.ORA
info = LISTENER=
(DESCRIPTION= (ADDRESS_LIST=
(ADDRESS_LIST=
(ADDRESS=
(ADDRESS=
(PROTOCOL=tcp)
(PROTOCOL=tcp)
(HOST=brinfoa01) (HOST=brinfoa01)
(PORT=1521) (PORT=1521)
) )
) )
(CONNECT_DATA= SID_LIST_LISTENER=
(SID=BRBINFO1) (SID_LIST=
) (SID_DESC=
) (SID_NAME=BRBINFO1)
(ORACLE_HOME=/oracle7/oracle7)
(ENVS='EPC_DISABLED=TRUE')
)
)
 SQLNET.ORA STARTUP_WAIT_TIME_LISTENER=0
# SQLNET.EXPIRE_TIME = 0 CONNECT_TIMEOUT_LISTENER=0
LOG_DIRECTORY_LISTENER=/oracle7/oracle7/network/log
SQLNET.AUTHENTICATION_S
LOG_FILE_LISTENER=listener
ERVICES=(none, beq)
TRACE_LEVEL_LISTENER=OFF

45. Net8
Networking Challenge
 Support large mission-critical
client/server, and provide migration
path towards distributed object
architecture
 Net8 Focus
1. Scalability : Connection Pooling, Multiplexing(Connection Manager)
2. Manageability : Configuration-free installation option,
Centralized client administration, Automated client configuration
3. Security : Oracle Security Server

46. ODBC / oo4o / JDBC
 ODBC (Open Database Connectivity )
- Provide a way for client program (eg VB, Excel, Access) to access database
- is a standardized API, developed according to the specification of the SQL
Access Group, than allows one to connect to SQL database
 oo4o (Oracle Object for OLE)
- a middleware product manufactured by Oracle that allows native access to Oracle7
databases from client applications via the Microsoft OLE standard
- OLE 2.0 Automation Server, Oracle Data Control, Two C++ Class Library
 JDBC (Java Database Connectivity )
- a set of classes and interfaces written in Java to allow other Java programs to send
SQL statements to a relational database management system
- JDBC Thin for Java applets, JDBC OCI for Java application