E-R Diagram Introduction:- In 1976 ‚Chen developed the Entity-Relationship Diagrams ‚a high-level data model that is useful in developing a conceptual design for database . An ER diagram is a diagram containing entities or “items”‚ relationships among them‚ and attributes of the entities . The E-R model is one of the best known tools for logical database design. Within the database community‚ it is considered a natural and easy-to-understand way of conceptualizing the structure of database.
Premium Entity-relationship model
1. What is an Entity Relationship Diagram? An entity relationship diagram is a graphical representation of an organisation’s data storage requirements. Entity relationship diagrams are abstractions of the real world which simplify the problem to be solved while retaining its essential features. Entity relationship diagrams are used to: identify the data that must be captured‚ stored and retrieved in order to support the business activities performed by an organisation; and identify the data required
Premium Entity-relationship model Relationship
Exercises 9 address driver-id person name owns license model year car report-number location date driver participated accident damage-amount Figure 2.1 E-R diagram for a Car-insurance company. Exercises 2.1 Explain the distinctions among the terms primary key‚ candidate key‚ and superkey. Answer: A superkey is a set of one or more attributes that‚ taken collectively‚ allows us to identify uniquely an entity in the entity set. A superkey may contain extraneous attributes
Premium Entity-relationship model
2013 Week 4 Problems and Exercises Chapter 7 5) Consider the E-R diagram in Figure 7-20. Based on this E-R diagram‚ answer the following questions: a. How many EMPLOYEES can work on a project? There is no set limit of employees to work on one given project. b. What is the degree of the Used on relationship? There are 2 degrees for the Used on relationship. c. Do any associative entities appear in this diagram? If so‚ name them. Yes there is task which is an associative entity.
Premium Entity-relationship model
Contents ERD (Entity Relation Diagram) 2 2.1 History of ERD 2 2.2 Building Blocks 2 2.2.2 Relationship 2 2.3. Diagramming Conventions 3 MS ACESS TABLE 5 3.1 Parts of Table 6 3.2 Creating Tables in Access 6 Chapter No 2 ERD (Entity Relation Diagram) 2.1 History of ERD An entity-relationship model (ERM) is an abstract and conceptual representation of data. Entity-relationship modeling is a database modeling method‚ used to produce a type of conceptual schema or semantic data
Premium Entity-relationship model Microsoft Access
Set Operations and Venn Diagrams " Please respond to the following: QUES: Create a story problem that demonstrates how a Venn diagram could be used to illustrate combined operation with sets. ANS: Use a Venn diagram to illustrate the following scenario: There are 40 people in a drum corp. Of the 40 people‚ 20 play the snare drum; 10 play the trumpet; 5 plays the cymbals. There are 5 people that play both the snare drum and cymbals; and 3 play all three instruments. How many people don’t play
Premium Venn diagram Diagram Drum kit
Chapter 4 The Enhanced E-R Model and Business Rules Chapter Objectives The purpose of this chapter is to present some important extensions to the E-R model (described in Chapter 3) that are useful in capturing additional business meaning. In particular we describe two types of extensions to the E-R model. The enhanced entity-relationship (EER) model includes constructs for supertype/subtype relationships. The inclusion of new notation for business rules allows the designer to capture
Premium Entity-relationship model Object-oriented programming Object
...TO THE PEOPLE OF GOD (AND THE PEOPLE I LOVE) Christians talk a lot about premarital sex. And I think that’s a mistake. I don’t think it’s a mistake because the issue is unimportant but because the grammar is skewed. The word “fornication” is almost gone from contemporary Christian speech. It sounds creepy and antiquated. Instead‚ we talk about “abstinence” and “premarital sex.” In the most recent issue of Touchstone magazine‚ I argue that the loss of the words “fornicate” and “fornication”
Premium Marriage Sexual intercourse Christianity
The Normal Forms 3NF and BCNF Yunliang Jiang Housekeeping • HW2 due tonight – Upload a single PDF/DOC file to Compass • Stage 3 due tonight • Midterm tomorrow – During class time. Preview • • • • • • Normalization Solution: Normal Forms Introducing 3NF and BCNF 3NF Examples BCNF Normalization • Normalization is the process of efficiently organizing data in a database with two goals in mind • First goal: eliminate redundant data – for example‚ storing the same data in more than one table
Premium Database normalization
e-Business Model‚ Venn Diagram Technology Application and e-Marketing – MKT552 February 18‚ 2013 Howard Kersey Introduction The e-Business sector is seeing tremendous growth at a time when technology is the lifeline for many people. Online business models are used to convert new technology to economic value. For some start-up companies‚ familiar business models cannot be applied‚ so a new model must be devised to fit the vision for the new entity. Not only is the business model important
Premium Strategic management Management Marketing