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CHAPTER 1: Introduction to Client/Server Databases. A GUIDE TO ORACLE8. 1. File-Based Approach to Data Processing. Checking Account Data Files. Checking Account Programs. Figure 1-1. Auto Loan Data Files. Auto Loan Programs. Savings Account Data Files. 1. Savings
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CHAPTER1: Introduction to Client/Server Databases A GUIDE TO ORACLE8 1
File-Based Approach to Data Processing Checking Account Data Files Checking Account Programs Figure 1-1 Auto Loan Data Files Auto Loan Programs Savings Account Data Files 1 Savings Account Programs
Redundant programs Duplicate data Inconsistent data Problems with Data File Approach 1
Database Approach to Data Processing Checking Account Programs Organizational Database Database Management System Auto Loan Programs Figure 1-2 Savings Account Programsh 1
Single user’s desktop computer DBMS and Client Database applications are stored on user’s workstation All files are transmitted across network Personal Databases 1
Network Personal Database Structure File Server 1. “Listens” for file requests. 2. Sends and receives files. Figure 1-3 File Requests Updated Files Requested Files File Requests Updated Files Requested Files User 1 Client Workstation (DBMS Application & Client DB Applications) 1. Send file requests. 2. Receives files. 3. Filter data from files and/or 4. Add new data to files. User 2 Client Workstation (DBMS Application & Client DB Applications) 1. Send file requests. 2. Receives files. 3. Filter data from files and/or 4. Add new data to files. 1
DBMS process runs on server Client applications run on user’s workstation Data requests are transmitted to DBMS DBMS only returns filtered data Client/Server Databases 1
Network Client/Server Database Structure Database Server (DBMS Process) 1. “Listens” for data requests, new data, and updates. 2. Filters requested data from the database and sends it to client. Figure 1-4 Data Request. Data input/update Data Request. Data Input/Update. Filtered Data Filtered Data User 1 Client Workstation (Client DB Application) 1. Send data request. 2. Receive filtered data. or 3. Send data input or update. User 2 Client Workstation (Client DB Application) 1. Send data request. 2. Receive filtered data. or 3. Send data input or update. 1
Handling server and client failures Processing transactions Handling high data volumes Providing security Servicing multiple simultaneous users Other Advantages of Client/Server Databases 1
SQL*Plus PL/SQL Developer Procedure Builder Query Builder Form Builder Report Builder Graphics Builder Project Builder Oracle Application Server (Web pages) The Oracle8 Environment 1
Hierarchical Parent-to-child relationships Relationships maintained using pointers Relational Data stored in tables Relationships created through shared key fields Overview of Databases 1
Hierarchical Database 1 Figure 1-5
Table: Matrix with columns and rows Column: Data category Also called fields Row: Contains actual data values Also called records Relational Database Terms 1
Relational Database With Two Tables 1 Figure 1-6
Primary key: Field whose value must be unique for each record Candidate key: Field that could be used for primary key Foreign key Value must be a primary key in another table Used to create a relationship Relational Database Terms 1
Creating a Relationship With a Foreign Key 1 Figure 1-7
Composite key: Primary key created using multiple fields Surrogate key: Numerical value generated by the database for use as a primary key Relational Database Terms 1
Example of a Composite Primary Key Figure 1-8 1
Clearwater Traders Mail-order clothing and sporting goods retailer Northwoods University University registration system Case Study Databases 1
CUSTOMER CUST_ORDER ITEM INVENTORY SHIPPING BACKORDER ORDERLINE COLOR ORDERSOURCE Clearwater Traders Tables 1
Lookup table: List of legal values for a field COLOR ORDERSOURCE Lookup Tables 1
STUDENT FACULTY LOCATION TERM COURSE COURSE_SECTION ENROLLMENT Northwoods University Tables 1