Draw ERDs.

$1.$ A book is identified by its ISBN number, and it has a title, a price, and a date of publication. A book is written by one or multiple authors. Each author is identified by an author number and has a name and date of birth. Each author has either one or multiple books; in addition, occasionally data are needed regarding prospective authors who have not yet published any books.

$2.$ Pine Valley Furniture Company needs to capture the following information about its $1$employees in a database. John is an employee with employee ID $1924435$ who lives in Newark, NJ and who is $34$ years old. Elizabeth is an employee with employee ID $5636768$ who lives in Dover, DE and who is $25$ years old. Her phone number is $302-331-3331.$ David is an employee with employee ID $3464577$ who lives in Wilmington, DE and who is $50$ years old. David has two phone numbers in record: $302-220-2330$ and $520-221-5552.$ John and David are carpenters. The code for carpenter is CAP. All carpenters are paid $$10/$hour $($wage$).$ Elizabeth is a manager. The code for manager is MAN. All managers are paid $$30/$hour $($wage$).$

$3.$ A piano manufacturer wants to keep track of all the pianos it makes individually. Each piano has an identifying serial number and a manufacturing completion date. Each piano represents exactly one piano model, all of which have an identification number and a name. Over time, the company often manufactures thousands of pianos of a certain model, and the model design is specified before any single piano exists.

$4.$ Double Happiness, a bus company, records the following information for all their bus trips: a unique trip#$,$ date and time of departure, date and time of arrival, and a description of the trip. Double Happiness also wants to know the station of departure and the station of arrival. Double Happiness keeps the following information for all possible stations in the USA, even when they don$$t have any trips scheduled for that station: a unique code, name, and location. A trip always departs from exactly one station. Many trips depart from the same station $($e$.$g$.$ Wilmington$).$ A trip can arrive at only one station. Many trips can arrive at the same station $($e$.$g$.$ NYC$).$ Trip information and the station of departure are recorded at the same time $$ one hour before departure. The station of arrival is recorded one hour after arrival.

$5.$ Bell Electric Company wishes to create a database to record the following information:

Customers are identified by Customer ID$,$ and need to have their Name, Billing Address $($including Street, City, State, and Zip Code$),$ and Telephone number recorded. Bell Electric charges the customers based on their locations. Each location has a unique Location ID$,$ Address $($Street$,$ City, State, Zip Code$),$ and Type $($values of Business or Residential$).$ Most customers have just one location but customer Jeff Bazos is a property owner and he owns three locations. $32$ Country Dr$.$ is a house being rented to $3$ different people and therefore it has multiple customers. However, $30$ Country Dr$.,$ the neighboring location of $32$ Country Dr$.,$ is currently vacant and therefore does not have a customer.

$6.$ Prepare an ERD for the Garden Real Estate Firm that lists property for sale. The following describes this organization:

$$ The firm has a number of sales offices in several states. Attributes of sales office include Office Number $($identifier$)$ and Location.

$$ Each sales office is assigned one or more employees. Attributes of employee include Employee ID $($identifier$)$ and Employee Name. An employee must be assigned to only one sales office.

$$ For each sales office, there is always one employee assigned to manage that office. An employee may manage only the sales office to which he or she is assigned.

$$ The firm lists property for sale. Attributes of property include Property ID $($identifier$)$ and Location. Components of Location include Address, City, State, and Zip Code.

$$ Each unit of property must be listed with one $($and only one$)$ of the sales offices. A sales office may have any number of properties listed or may have no properties listed.