E-R diagram assignment PDF

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Assignment 1Description:Automata, Inc., produces specialty vehicles by contract. The company operates several departments, each of which builds a particular vehicle, such as a limousine, truck, van, or RV. Before a new vehicle is built, the department places an order with the purchasing department t...

Description

Assignment 1 Description: Automata, Inc., produces specialty vehicles by contract. The company operates several departments, each of which builds a particular vehicle, such as a limousine, truck, van, or RV. • Before a new vehicle is built, the department places an order with the purchasing department to request specific components. Automata’s purchasing department is interested in creating a database to keep track of orders and to accelerate the process of delivering materials. • The order received by the purchasing department may contain several different items. An inventory is maintained so the most frequently requested items are delivered almost immediately. When an order comes in, it is checked to determine whether the requested item is in inventory. If an item is not in inventory, it must be ordered from a supplier. Each item may have several suppliers. Given that functional description of the processes at Automata’s purchasing department, do the following: 1) Create two data models, External and Conceptual using Crow’s foot Entity Relationship Diagram (ERD). Make sure to: A. Identify all of the main entities. B. Identify all of the relations and connectivities among entities. C. Identify the type of existence dependence in all the relationships. A. External Models: Business Rule 1: Before a new vehicle is built, the department places an order with the purchasing department to request specific components. Automata’s purchasing department is interested in creating a database to keep track of orders and to accelerate the process of delivering materials.

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Business Rule 2: The order received by the purchasing department may contain several different items. An inventory is maintained so the most frequently requested items are delivered almost immediately. When an order comes in, it is checked to determine whether the requested item is in inventory. If an item is not in inventory, it must be ordered from a supplier. Each item may have several suppliers.

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B. Conceptual Model:

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2) Discuss the benefits of developing each level of abstraction. You may cite your discussion. The advantages of developing external and conceptual level of abstraction are mentioned further. External Model: The external model is called the end user’s view of the data. The term end users refer to people who use the application programs (e.g., Purchasing Department) to manipulate the data and generate information. End users usually operate in an environment in which an application has a specific business unit focus. Generally, a database is an enterprise system that serves the needs of multiple departments. However, one department is not interested in seeing other departments’ data. Companies are generally divided into several business units, such as sales, finance, marketing and so on. For instance, a specific department in the business rules mentioned previously, is not directly concerned about from where items are coming; either directly from supplier or through inventory. It is only concerned with placing order with purchasing department. Each view level describes the database part that a particular user group is interested and hides the remaining database from that user group. This view level describes the end user interaction with database systems. Conceptual Model: The conceptual level data model describes the structure of the whole database; all business rules in one picture. The conceptual level describes what data are to be stored in the database and what relationship exist among data entities. That is, conceptual view helps database designers to determine database tables and also, which implementation tools to use.

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