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. Objectives (continued)
Understand the Northwoods University student registration database and the Clearwater Traders sales order database
Guide to Oracle 10g

4. 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 10g.
Guide to Oracle 10g

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

6. 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

7. 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

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

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

10. 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

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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. Database Design Main tasks involved with design of database:
Developing entity-relationship (ER) model
Normalizing database tables
Guide to Oracle 10g

20. Entity-Relationship Model
Designed to help you identify which entities need to be included in database
Composed of
Squares representing entities
Lines representing relationships
Types of relationships:
One to one (1:1)
One to many (1:M)
Many to many (N:M)
Guide to Oracle 10g

21. Entity-Relationship Model (continued)
One to one (1:1)
Each occurrence of a specific entity is found only once in each set of data
Rare in relational databases
One to many (1:M)
Instance can only appear once in one entity, but one or more times in the other entity
Guide to Oracle 10g

22. Entity-Relationship Model (continued)
Many to many (N:M)
Instance can occur multiple times in each entity
Cannot be represented in physical database
Broken down into series of two or more 1:M relationships through use of linking table in process of normalization
Guide to Oracle 10g

23. Normalization
Step-by-step process used to determine which data elements should be stored in which tables
Purpose
Eliminate data redundancy
Several levels of normalization
Forms
Guide to Oracle 10g

24. Normalization (continued)
Unnormalized data
Does not have a primary key identified
Contains repeating groups
First normal form (1NF)
Repeating groups removed
Primary key field identified
Guide to Oracle 10g

25. Example of Unnormalized Data
Guide to Oracle 10g

26. Normalization (continued)
Second normal form (2NF)
In 1NF
No partial dependencies
Partial dependency
Fields within the table are dependent only on part of the primary key
Guide to Oracle 10g

27. Normalization (continued)
Basic procedure for identifying partial dependency:
Look at each field that is not part of the composite primary key
Make certain you are required to have both parts of the composite field to determine the value of the data element
Guide to Oracle 10g

28. Normalization (continued)
Third normal form (3NF)
In 2NF
No transitive dependencies
Transitive dependency
Field is dependent on another field within the table that is not the primary key field
Guide to Oracle 10g

29. 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

30. 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

31. Personal Database Management Systems
DBMS and database applications run on same workstation
Appear to user as a single integrated application
Used primarily for creating single-user database applications
Can also be used for some multiuser applications
Should be used only for applications that are not mission critical
Guide to Oracle 10g

32. Personal Database Management Systems (continued)
Microsoft Access
Stores all data for database in a single file with an .mdb extension
Database administrator stores .mdb file on a central file server
Guide to Oracle 10g

33. Using a Personal Database for a Multiuser Application
Guide to Oracle 10g

34. Personal Database Management Systems (continued)
Transaction processing
Grouping related database changes into units of work that must either all succeed or all fail
DBMS can use the transaction log to reverse—or roll back—the changes
Guide to Oracle 10g

35. 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

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

37. 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

38. 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

39. 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

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

41. 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

42. The Database Cases Fictional organizations: Design principles:
Clearwater Traders
Northwoods University
Design principles:
Convert all tables to third normal form
Include primary key as foreign key in table on “many” side of relationship
Specify data type for each column
Guide to Oracle 10g

43. The Clearwater Traders Sales Order Database
Clothing and sporting goods through mail-order catalogs
Wants to begin accepting orders using Web site
Required data consists of information for:
Customers
Orders
Items
Shipments
Guide to Oracle 10g

44. The Clearwater Traders Sales Order Database (continued)
Tables:
CUSTOMER
ORDER_SOURCE
ORDERS
CATEGORY
ITEM
Guide to Oracle 10g

45. The Clearwater Traders Sales Order Database (continued)
Tables (continued): :
ORDER_LINE
SHIPMENT
INVENTORY
SHIPMENT_LINE
COLOR
Guide to Oracle 10g

46. Visual Representation of the Clearwater Traders Database
Guide to Oracle 10g

47. The Northwoods University Student Registration Database
Student registration system
Data items consist of information about:
Students
Courses
Instructors
Student Enrollment
Guide to Oracle 10g

48. The Northwoods University Student Registration Database (continued)
Tables:
LOCATION
FACULTY
STUDENT
TERM
COURSE
COURSE_SECTION
ENROLLMENT
Guide to Oracle 10g

49. Visual Representation of the Northwoods University Database
Guide to Oracle 10g

50. Summary Relational databases Primary key Foreign key
Store data in tabular format
Create relationships that link related data using key columns
Primary key
Column that uniquely identifies specific record
Foreign key
Creates relationship between two tables
Guide to Oracle 10g

51. Summary (continued) Entity-relationship (ER) model
Used to describe types of relationships between entities
Normalization process
Used to determine which fields belong in which tables
Database system consists of
DBMS
Database applications
Guide to Oracle 10g

52. Summary (continued) Client/server databases divide database into
Server process that runs on network server
User application processes that run on individual client workstations
Oracle 10g is a client/server database
Guide to Oracle 10g