1 Client/Server Databases and the Oracle Relational Database

2  Each application has data files that correspond to only that application File-Based Data Processing Checking Account Programs Auto Loan Programs Savings Account Programs Checking Account Data Files Savings Account Data Files Auto Loan Data Files

3  Each application must have duplicate programs for file- handling operations  Duplicate data exists in each application’s data files  Duplicate data can become inconsistent Problems with File-Based Processing

4 Database Processing All applications interface with the same data in a central database Database Management System Checking Account Programs Auto Loan Programs Savings Account Programs Database

5 Database Processing Database Management System (DBMS) provides central set of common functions to manage data: Insert Update Retrieve View Oracle is a relational, client/server DBMS

6 Types of Database Systems Hierarchical: data relationships are maintained using pointers Pointers create links using physical hardware locations Relational: data relationships are maintained using shared data values called key fields

7 Hierarchical Databases Parent Data Child Data Pointer

8 Relational Databases Data is organized in tables Columns (fields) represent different data categories Rows (records) contain actual data values PRODUCT_IDDESCRIPTIONQUANTITY_ON _HAND 1Plain Cheesecake8 2Cherry Cheesecake10 Records Fields

9 Relational Table Keys Primary key: uniquely identifies a record Must be unique for each record Cannot be NULL (undefined) Candidate key: field that could be used as a primary key Surrogate key: numeric field created for the purpose of being the primary key

10 Relational Table Keys Foreign key Field in a table that is a primary key in another table Creates a relationship between the 2 tables Foreign key values must exactly match

11 Table Relationships PRODUCT_IDDESCRIPTIONQUANTITY_ON _HAND 1Plain Cheesecake8 2Cherry Cheesecake10 ORDER_IDPRODUCT_IDORDER_QUANTITY Primary Key Foreign Key

12 Composite Key Primary key made of the combination of two or more fields ORDER_IDPRODUCT_IDORDER_QUANTITY Composite Key

13 Database System Architectures Mainframe databases Both DBMS and applications run on mainframe computer Users access database and applications using terminals Personal databases Both DBMS and applications run on user’s workstation Client/server databases DBMS runs on central server Applications run on user’s (client) workstation

14  Handling server and client failures  Processing transactions  Handling high data volumes  Providing security  Servicing multiple simultaneous users Advantages of Client/Server Databases

15  Enterprise Edition (on central DB server) Or  Oracle Personal Edition  Personal database that acts just like a client/server database The Oracle Environment (Server Side)

16  SQL*Plus & PL/SQL  Developer  Procedure Builder  Form Builder  Report Builder  Graphics Builder  Project Builder The Oracle Environment: Client Side

17 What do you need for this class? Oracle Express Edition (any version) Works on Linux or Windows, NO OSX compatible version yet.