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It outlines six design steps, then explains how to identify entities, relationships, stored information, and integrity constraints. The material defines entities, entity sets, attributes, attribute domains, and keys, including superkeys and primary keys. 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A primary key is the key chosen as the principal identifier, and only primary keys are shown in ER diagrams (underlined).",{"name":123,"@type":110,"acceptedAnswer":124},"How are integrity constraints and key constraints represented in the material?",{"text":125,"@type":113},"The notes express constraints formally with logical rules (quantifiers and equalities) and also provide a datalog-like notation example, such as Emp(SIN, Name, Phone) with rules that enforce consistency of key attributes.","https://schema.org",{"og:url":83,"og:type":128,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":130,"canonical":83},"index,follow",{"doc_id":132,"site_id":62},655991,1793051489,{"code":4,"msg":5,"data":135},{"doc_id":132,"user_id":136,"nickname":92,"user_avatar":137,"doc_module":4,"category_id":29,"category_name":30,"doc_title":65,"doc_description":67,"doc_content":138,"file_id":139,"file_url":140,"file_type":141,"file_size":142,"view_count":81,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":36,"language":143,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":144,"faqs":145,"seo_title":146,"seo_description":67,"update_tm":147,"read_time":148},549768702563,"https://ap-avatar.wpscdn.com/avatar/8000c4aa63b76e948b?x-image-process=image/resize,m_fixed,w_180,h_180&k=1786536092046926083","UNIT 2  \nConceptual Database Design  \nRead Text, Chapter 2  \nUnit 2 Laks V.S. Lakshmanan; Based on Ramakrishnan & Gehrke, DB Management Systems 1  \nLearning Goals  \nGiven a problem description,  \n􀂄 create an Entity-relationship (ER) diagram with the correct entities and relationships that accurately model the problem’s data  \n􀂄 Accurately represent entities that depend on other entities, or inherit from other entities or have n-ary relationships with other entities, in the ER model created.  \n􀂄 identify alternative representations of the problem concepts and evaluate the choices  \n􀂾 compare alternative ER models for the same domain and identify their strengths and weaknesses  \nDatabase Design  \nConsists of 6 steps:  \n􀂄 Requirements Elicitation & Analysis  \n􀂾 common to all application designs; covered in CPSC 310  \n􀂄 Conceptual Database Design  \n􀂾 produces a high level description of data (semantic models)  \n􀂄 Logical Database Design  \n􀂾 converts conceptual design into a DB schema (logical schema)  \n􀂄 Schema Refinement  \n􀂾 restructuring to satisfy desirable properties (normalization)  \n􀂄 Physical Database Design  \n􀂾 deals with how the instances (actual data) will be stored on disk  \n􀂄 Application & Security Design  \n􀂾 general application design  \n􀂾 applications are restricted to only access data that they need  \nUnit 2 3  \nConceptual Database Design  \nMain goal: Given the requirements for an application, identify:  \n1. Entities and relationships in the application’s domain  \n􀂾 Entities are usually nouns, but avoid irrelevant nouns  \n􀂾 e.g. , At UBC, we have full-time and part-time students. We store such information in our computer. We have 1000’s of courses…; Spielberg is a director who lives in Beverly Hills, CA.  \n􀂾 Relationships are statements about 2 or more objects. Often, verbs.  \n􀂾 e.g. , Hopkins stars in Fracture; Mary took CPSC404 and earned anA+; Tom rated Sky Fall at five stars.  \n2. Information about these entities and relationships that should be stored in the database  \n3. Integrity constraints or business rules that hold  \n􀂾 For relational databases, the ER Model is used at this stage.  \n􀂾 The enterprise data is usually represented by an ER diagram.  \nER Model Basics: Entities  \n􀂄  Entity: Real-world object distinguishable from other objects, whose data is important for the application.  \n􀂄 An entity is described using a set of properties, called attributes.  \n􀂄  Entity Set: A collection of similar entities. E.g. , all employees of an organization.  \n􀂾 All entities in an entity set have the same set of attributes, i.e. , same schema. (Until we consider ISA hierarchies, anyway!)  \n􀂾 Each attribute has a domain. (e.g.., float, string, date, int, color)  \n􀂾 Each entity set has a key.  \nKeys  \n􀂄 Distinguish entities  \n􀂄 A key is the minimal set of one or more attributes which, taken collectively, identify uniquely an entity in an entity set.  \n􀂄 A superkey is a key plus zero or more other attributes in the entity set  \n􀂄 A primary key is the key chosen as the principal means to identify entities in an entity set – it’s a matter of designation  \n􀂄 Only primary keys are shown in ER diagrams (underlined attributes)  \n􀂄 We’ll discuss superkeys when we consider normal forms (for now, don’t worry about them)  \nStreet  City  House \\#  Address   \nUnit 2 6  \nKeys  \n􀂄 Distinguish entities  \n􀂄 A key is the minimal set of one or more attributes which, taken collectively, identify uniquely an entity in an entity set.  \n􀂄 A superkey is a key plus zero or more other attributes in the entity set  \n􀂄 A primary key is the key chosen as the principal means to identify entities in an entity set – it’s a matter of designation  \n􀂄 Only primary keys are shown in ER diagrams (underlined attributes)  \n􀂄 We’ll discuss superkeys when we consider normal forms (for now, don’t worry about them)  \nStreet  City  House \\#  Address   \nKey Constraint: E – entity Set; K set of key attributes; says  \n∀􀝁 􀯜 , 􀝁􀯝 ∈ 􀜧: 􀝁 􀯜. 􀜭 = 􀝁􀯝 . 􀜭→ 􀝁 􀯜 = 􀝁􀯝 .  \nUnit 2 ","cbCaiiTLff2mvDqf","https://ap.wps.com/l/cbCaiiTLff2mvDqf","pdf",678312,"English","# Learning Goals\n# Database Design Process\n# Conceptual Database Design Main Goal\n## ER Model Basics: Entities\n## Keys and Key Constraints\n# Keys in Datalog-like Notation","[{\"question\":\"What is the main goal of conceptual database design in Unit 2?\",\"answer\":\"Given an application’s requirements, identify the entities and relationships in the domain, determine what information about them must be stored, and specify integrity constraints or business rules that must hold.\"},{\"question\":\"How does the ER model distinguish entities and relationships?\",\"answer\":\"Entities are typically nouns representing real-world objects important to the application, while relationships are statements about two or more objects, often expressed using verbs.\"},{\"question\":\"What is a key, and how is a primary key used in ER diagrams?\",\"answer\":\"A key is the minimal set of one or more attributes that uniquely identifies an entity in an entity set. A primary key is the key chosen as the principal identifier, and only primary keys are shown in ER diagrams (underlined).\"},{\"question\":\"How are integrity constraints and key constraints represented in the material?\",\"answer\":\"The notes express constraints formally with logical rules (quantifiers and equalities) and also provide a datalog-like notation example, such as Emp(SIN, Name, Phone) with rules that enforce consistency of key attributes.\"}]","Unit 2 - Conceptual Database Design - ER Model Basics - Entities and Keys | PDF",1792965389,101]