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.
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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
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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
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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.
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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
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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
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...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”
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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
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In regards to the speech in figure 11-9 I would improve the style of the speech in a different way. In addition after reading about oral reports I get a clear understanding the importance of business communication and the manner in which an individual is been treated by their colleagues in a facility or company. The manner in which I would improve the style of Ethanol in Fuel speech‚ I would begin with a greeting depending on the type of day such as Good morning or Good afternoon‚ several of these
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Jennifer Hauss March 4‚ 2015 Bacterial Transformation Lab Report Introduction In this lab‚ the goal was to transform the bacteria e-coli to glow in the dark (or under a black light). Four plates were set up with agar in them for the bacteria to feed on and grow. Changes were then made to the bacteria. One plate was the control plate‚ having only the LB or agar for the bacteria and negative pGLO‚ which is the liquid not containing the plasmid. This is the plate that was compared with the three
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