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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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 model of a
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Draw the Entity- Relationship Diagram (ERD) for the following scenario: A salesperson may manage many other salespeople. A salesperson is managed by only one salespeople. A salesperson can be an agent for many customers. A customer is managed by one salespeople. A customer can place many orders. An order can be placed by one customer. An order lists many inventory items. When the order is made for number of inventory items‚ the date and the amount is recorded. An inventory item may be listed
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At the request of the Huffman Trucking Maintenance Department‚ Smith Consulting developed entities and attributes for their Fleet Trucking Maintenance database. Unfortunately‚ the creator of the database was not available and the development of the database system was not able to be completed. D Team realizes that the development of a reliable database system is needed to provide for the tracking of scheduled and unscheduled maintenance for their fleet. Therefore‚ a database along with forms‚ tables
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Data Models The quest for better data management has led to different models that attempt to resolve the file system’s critical shortcomings. Because each data model evolved from its predecessors‚ it is essential to examine the major data models in roughly chronological order. 1.1 The Hierarchical Model A Hierarchical Database Model is a data model in which the data is organized into a tree-like structure. The structure allows representing information using parent/child relationships: each
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Business Rules and Data Models Strayer University CIS-111 Prof. A database is a structure that contains information about many different categories of information and about the relationships between those categories (Pratt & Adamsk 2010). Database objects are entities that exist within a database to support operations such as storing‚ retrieving and manipulating data. Organizations use large amounts of data and database management system to store and transform data into information to support
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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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savour foods | Savour Food Document | Conceptual and relational data model | | Submitted toMiss sarfrazSubmitted by Saba luqman | 6/26/2013 | Who we are? Countless are the bounties of our Lord Almighty. The minerals lying hidden inside the bowels of mother earth‚ the sundry season and the various crops sprouting and flourishing in those seasons and then their mouth-watering‚ tastes tickling our buds – ”Oh which of Allah’s blessings can you deny.” Same are the tastes that we extracted
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breakdown of relationships. On model that relates to the breakdown of relationships is Lee’s model on the dissolution of relationships. He came up with an alternative explanation of relationship breakdown based in his survey of 112 romantic break-ups. He discovered evidence for 5 distinct stages: Dissatisfaction‚ Exposure of the problem‚ Negotiating in order to come to an agreement‚ Resolution is where there is some attempt to resolve the problem and Termination is where the relationship comes to
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throughput times whilst maintaining a good level of resources utilization. For analysing the production line‚ a simulation model was built using Arena software program‚ based on information provided by company. The purpose of using Arena simulation software is to help demonstrate‚ predict‚ and measure system strategies for effective‚ efficient and optimized performance. The model was built using the following input data: For manufacturing three different products (P1‚P2‚P3) the company uses five components
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