Entity-Relationship (E/R) Model Dr P Sreenivasa Kumar Professor CS&E Dept I I T Madras Entity-Relationship (E/R) Model Widely used conceptual level data model • proposed by Peter P Chen in 1970s Data model to describe the database system at the requirements collection stage • high level description. • easy to understand for the enterprise managers. • rigorous enough to be used for system building. Concepts available in the model • entities and attributes of entities. • relationships between
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Why are Living Organism so Diverse ? Regardless of world’s life diversity‚ we all‚ from the ant to the whale and us humans have DNA linkage‚ which gives us the evidence for one common ancestor. The question that comes up now is how from this very primitive common ancestor did we all end up so diverse. Biologist have dedicated they life to answer this question‚ Through this essay I shall show how through different aspects life has become so diverse. Timescale Life as not evolve suddenly from its
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Cells‚ Tissues and Organs of the Digestive System Living organisms all have various functioning systems within the body that enable life processes to be carried out. Each system uses different organs that coordinate with each other to carry out their functions‚ and these systems‚ organs and functions are shown below: Functioning System Related Organs Function Circulatory Heart‚ Arteries‚ Veins Transports blood through the body Digestive Mouth‚ Tongue‚ Pharynx‚ Esophagus‚ Liver‚ Stomach
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All living organisms are composed of one or more cells‚ and like any living organism‚ cells are made up of smaller structures that help them function. In the context of cells‚ these smaller structures are referred to as organelles and each organelle has its own unique function that has developed over time. While we are typically aware of how these organelles function‚ how they evolved raises several questions. The main model for how eukaryotic cells evolved over time is the endosymbiont theory. This
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alternate meanings see skin (disambiguation) Diagram of the layers of human skinIn zootomy and dermatology‚ skin is an organ of the integumentary system composed of a layer of tissues that protect underlying muscles and organs. As the interface with the surroundings‚ it plays the most important role in protecting against pathogens. Its other main functions are insulation and temperature regulation‚ sensation and vitamin D and B synthesis. Skin has pigmentation‚ provided by melanocytes‚ which absorbs
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Designer Babies The first batch of genetically modified babies were created in 2001. Out of the 30 babies that were born‚ 15 were found to have DNA from three different adults. Although having DNA from more than two sources can occur naturally‚ these 15 babies were created with a method called “cytoplasmic transfer‚” which had been banned by the FDA . The method was initially developed to save female eggs that had been difficult to fertilize and was showing much promise—until tracking the growth
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Persuasive Essay Chris Lauture Period 2‚ Ms. Vough Going through life what would you do if your child had a disease or some sort of injury during birth? If so what would you do to save it or help your infant out? Well this has happened to a little girl by the name of Manar. On February 19‚ 2005‚ 10-month-old Manar underwent a successful 13-hour surgery in Egypt. The under developed conjoined twin‚ Islam‚ was attached to Manar’s head and was facing upward. Islam could smile
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Purpose: To find how pH and temperature levels affect the enzyme Background: Enzymes are a type of protein vital to sustaining life‚ it works with vitamins and minerals as a biological catalyst‚ which lowers the activation energy for a reaction to occur. Each individual type of enzyme does a specific job‚ and they do not die‚ they are reused. For example‚ catalase is an enzyme found in almost all living cells that will break down hydrogen peroxide and turn it into water and oxygen. The
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Problem Solutions 1. Use the following business rules to create a Crow’s Foot ERD. Write all appropriate connectivity’s and cardinalities in the ERD. 1.a. A department employs many employees‚ but each employee is employed by one department. 1.b. Some employees‚ known as “rovers‚” are not assigned to any department. 1.c. A division operates many departments‚ but each department is operated by one division. 1.d. An employee may be assigned many projects‚ and a project may have many employees
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The Everglades: A Food Web Diagram Name BIO/101 Date Dr. Doreen Sterling The Everglades: A Food Web Diagram The Everglades is a two million acre wetland ecosystem. The Everglades reaches from central Florida‚ near Orlando‚ all the way south to Florida Bay (National Wildlife Federation‚ 1996-2013). During the wet season‚ Lake Okeechobee overflows‚ releasing water into a slow moving‚ shallow river. The river is mostly saw-grass marsh. The Everglades is an ecosystem that hosts a large diversity
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