1. Client/Server Databases and the Oracle 10g Relational Database
Chapter 1:
Client/Server Databases and the Oracle 10g Relational Database
Guide to Oracle 10g

2. Objectives Develop an understanding of the purpose of database systems
Describe the purpose and contents of an entity-relationship model
Explain the steps in the normalization process
Describe the differences between personal and client/server databases
Guide to Oracle 10g

3. Introduction
If an organization needs to store and maintain a large amount of data that must be viewed and updated by many users at the same time, it often uses a client/server database such as Oracle 11g.
Guide to Oracle 10g

4. Database Systems Data files consist of: Fields Records
Describe characteristics
Also called columns
Records
Group of related fields
Guide to Oracle 10g

5. Database Systems (continued)
Problems with storing data in files:
Proliferation of data management programs
Presence of redundant data
Inconsistent data
Database
Stores all organizational data in central location
Eliminates redundant data to reduce possibility of inconsistent data
Guide to Oracle 10g

6. Database Systems (continued)
Database management system (DBMS)
Application that performs all routine data-handling operations
Provides central set of common functions for managing database
Inserting
Updating
Retrieving
Deleting data values
Guide to Oracle 10g

7. Database Approach to Data Processing
Guide to Oracle 10g

8. Database Systems (continued)
Database administrator
Person responsible for installing, administering, and maintaining the database
Often called DBA
Guide to Oracle 10g

9. Overview of Relational Databases
Table
Matrix with columns and rows
Columns
Represent different data fields
Characteristics or attributes about entity
Rows
Contain individual records
Attributes about a specific instance of entity
Guide to Oracle 10g

10. Overview of Relational Databases (continued)
Guide to Oracle 10g

11. Overview of Relational Databases (continued)
Entity
Object about which you want to store data
Different tables store data about each different entity
Relationships
Links that show how different records are related
Guide to Oracle 10g

12. Overview of Relational Databases (continued)
Key fields
Establish relationships among records in different tables
Main types of key fields
Primary
Candidate
Surrogate
Foreign
Composite
Guide to Oracle 10g

13. Primary Keys
Column in relational database table whose value must be unique for each row
Serves to identify individual occurrence of entity
Every row must have a primary key
Cannot be NULL
NULL
Value is absent or unknown
No entry is made for that data element
Guide to Oracle 10g

14. Candidate Keys Any column that could be used as the primary key
Should be a column that is unique for each record and does not change
Guide to Oracle 10g

15. Surrogate Keys Column created to be record’s primary key identifier
Has no real relationship to row to which it is assigned other than to identify it uniquely
Surrogate key values automatically generated using a sequence
Guide to Oracle 10g

16. Foreign Keys Column in table that is a primary key in another table
Creates relationship between two tables
Value must exist in table where it is the primary key
Guide to Oracle 10g

17. Composite Keys
Unique key that is created by combining two or more columns
Usually comprises fields that are primary keys in other tables
Composite
Key
ORDER_ID
PRODUCT_ID
ORDER_QUANTITY
100 1 2
200
Guide to Oracle 10g

18. Database Systems Consists of Server DBMS Database applications
Manages physical storage and data retrieval
Database applications
Provide interface that allows users to interact with database
Server
Computer that shares resources with other computers
Guide to Oracle 10g

19. Database Systems (continued)
Server process
Program that listens for requests for resources from clients
Responds to requests
Client
Program that requests and uses server resources
Guide to Oracle 10g

20. Client/Server Database Management Systems
DBMS server process runs on one workstation
Database applications run on separate client workstations across network
Server sends only requested data back to client rather than entire database
Guide to Oracle 10g

21. Client/Server Database Architecture
Guide to Oracle 10g

22. Client/Server Database Management Systems (continued)
Generate less network traffic than personal databases
Extra features to minimize chance of failure
Powerful recovery mechanisms that often operate automatically
Maintain file-based transaction log on database server
Guide to Oracle 10g

23. Client/Server Database Management Systems (continued)
Preferred for
Database applications that retrieve and manipulate small amounts of data from databases containing large numbers of records
Mission-critical applications
Web-based database applications that require increased security and fault tolerance
Guide to Oracle 10g

24. The Oracle 10g Client/Server Database
Latest release of Oracle Corporation’s relational database
Client/server database
Server side
DBMS server process
Oracle Net
Utility that enables network communication between client and server
Guide to Oracle 10g

25. Client/Server Architecture for Oracle 10g DBMS
Guide to Oracle 10g

26. The Oracle 10g Client/Server Database (continued)
Oracle Application Server
Used to create World Wide Web pages that allow users to access Oracle databases
Oracle client products:
SQL*Plus
Oracle 10g Developer Suite
Enterprise Manager
Guide to Oracle 10g