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Database Modeling with ER

Database Modeling with ER. Lab 2. since. name. dname. ssn. budget. lot. did. Works_In. Employees. Departments. Notations in ER. Entity and Attribute. Relationship. since. name. dname. ssn. lot. did. budget. Employees. Manages. Departments. Cont. Key Constraint. since.

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Database Modeling with ER

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  1. Database Modeling with ER Lab 2

  2. since name dname ssn budget lot did Works_In Employees Departments Notations in ER Entity and Attribute Relationship

  3. since name dname ssn lot did budget Employees Manages Departments Cont. Key Constraint

  4. since since name name dname dname ssn did did budget budget lot Departments Employees Manages Works_In since Cont. Participation Constraints

  5. name ssn lot Employees hours_worked hourly_wages ISA contractid Contract_Emps Hourly_Emps Cont. Class Hierarchies

  6. name ssn lot Employees Monitors until since started_on dname pid pbudget did budget Sponsors Departments Projects Cont. Aggregation

  7. Steps for ER • Identify Entities • Identify Attributes • Identify Relationships • Identify Constraints

  8. A Real-world Example I would like my customers to be able to browse my catalog of books and to place orders over the Internet. Currently, I take orders over the phone. I have mostly corporate customers who call me and give me the ISBN number of a book and a quantity. I then prepare a shipment that contains the books they have ordered. If I don’t have enough copies in stock, I order additional copies and delay the shipment until the new copies arrive; I want to ship a customers’ entire order together. My catalog includes all the books that I sell. For each book, the catalog contains its ISBN number, title, author, purchase price, sales price, and the year the book was published. Most of my customers are regulars, and I have records with their names and addresses. New customers have to call me first and establish an account before they can use my website. On my new website, customers should first identify themselves by their unique customer identification number. Then they should be able to browse my catalog and place orders online. (3rd edition textbook P49)

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