A composite primary key occurs when you define more than one column as your primary key. A char string can be up to 8,000 characters long. By definition, a primary key must be unique and must have a value (which is not null). How can you prevent the accidental loss of an entire table? Referential integrity How many bytes does a single character take up if it is a varchar that supports English and most European languages? 1 byte How many bytes does the int data type take up? 4 bytes
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Server architecture for DBMSs * Distributed Databases * Data Warehouse LECTURE FOUR: Database Design Process * Logical Database Design Process * Physical Database Design * Object-Oriented Database Design LECTURE FIVE: CAT LECTURE SIX: Modeling Data * Entity Relationship ER Model * Normalization LECTURE SEVEN: Introduction to Structured Query Language LECTURE EIGHT: Structured Query Language LECTURE NINE: Forms, Reports and Applications LECTURE TEN: Database Integrity and Security
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DBMS vs. RDBMS • Relationship among tables is maintained in a RDBMS whereas this not the case DBMS as it is used to manage the database. • DBMS accepts the ‘flat file’ data that means there is no relation among different data whereas RDBMS does not accepts this type of design. • DBMS is used for simpler business applications whereas RDBMS is used for more complex applications. • Although the foreign key concept is supported by both DBMS and RDBMS but its only RDBMS that enforces the rules. •
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Example Case to 3NF Tables Purpose The COIS20025 textbook and assignments have numerous exercises that require you to take a given case and generate a data design for the case. The data design will typically consist of an ERD, 3NF table designs including keys (obviously) and sample data. The purpose of this document is to give an example of how to do this. It walks you through the process of completing this task. Preparation This document draws on "Developing Entity Relationship Diagrams (ERDs)"
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1. Identify the entities and their relationships. Then create an ERD for the reservations system. 2. Create 3NF table designs for the system. 3. For each of the entities identified, design tables and identify the possible candidate keys, the primary key, a probable foreign key, and potential secondary keys. 4. Use sample data to populate the fields for three records. Data items must include reservation number, Route Number, Date, Origin, Destinations, Departure Time, Arrival Time, Passenger
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Chapter 1 Database Systems Discussion Focus How often have your students heard that “you have only one chance to make a good first impression?” That’s why it’s so important to sell the importance of databases and the desirability of good database design during the first class session. Start by showing your students that they interact with databases on a daily basis. For example, how many of them have bought anything using a credit card during the past day, week, month, or year? None of
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PRACTICE Activity 2: Unit 3 Assignment 1: Unit 3 True/False Questions 1) The logical design is independent of any database management system. Answer: True 2) The physical design is the logical design adapted to the constraints and features of the database management system. Answer: True 3) You should always try to create cross relationships between parent and tables. Answer: False 4) Naming conventions help support clarity and consistency in database design. Answer: True 5) One to one relationships
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COMPARING PERCEPTIONS OF THE SYSTEMS ANALYSIS AND DESIGN COURSE BRANDI N. GUIDRY University of Louisiana at Lafayette Lafayette, LA 70504 DAVID P. STEVENS University of Louisiana at Lafayette Lafayette, LA 70504 ABSTRACT Information Systems (IS) practitioners and educators have equal interest in the content of the Systems Analysis and Design Course (“SAD”). Previous research has examined instructors’ perceptions regarding the skills and topics that are most important in the teaching of the SAD
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Date: TO WHOM SO EVER IT MAY CONCERN He was employed in the said position from dates of dd/mm/yyyy and dd/mm/yyyy. He had worked 40 hours per week and his annual salary was xxxx per annum. Besides salary, he also had other benefits like performance bonus, house rent allowances, transport allowances and medical insurance. His Responsibilities were as follows * Database Analysis and Design: Enforcement of database standards; working with Development
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Chapter 1 1. What is the difference between Data and Information? a. Data: raw facts that describe the characteristics of an event that, in isolation, have little meaning b. Information: data organized in a meaningful way to be useful to the user 2. What makes Information useful? c. Data is often processed (aggregated, sorted, etc.) and then combined with the appropriate context d. Decision makers typically require useful information to make decisions e
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