### Question 2: Relational Model / Relational Algebra#### Consider the following schema:```Sailors(sid: integer, sname: string, rating: integer, age: real);Boats(bid: integer, bname: string, color: string);Reserves(sid: integer, bid: integer, day: date);```#### Symbols you may need:```∩ -- ∪ -- σ -- π -- ⨝ -- ρ```You may use anything that was covered in the slides.1. **Find the names of sailors who reserved a blue boat, have rating at least 8, and are older than 40.**2. **Find the names of sailors who reserved only blue boats.**3. **Find the names of sailors who reserved at least two boats.** (Similar to our example of “Find the students who earned at least two A’s”)4. **Find the names of sailors who reserved exactly two boats.** (The solution could be based on the previous question)5. **Given the following two records, will Tom and Peter be included in the resulting table of Q2-1 (Question 2 subquestion 1)? Show the reasons.**#### Data:- **Sailors:** - `123, Tom, NULL, NULL` - `124, Peter, NULL, 41` - **Boats:** - `1, ABC, Blue` - **Reserves:** - `123, 1, 10/19/2020` - `124, 1, 10/20/2020`---**Explanation:**The questions above require you to apply relational algebra to solve specific database management tasks. Break down each problem using appropriate symbols and operations taught during the course.**For example:**1. For **finding sailors who reserved a blue boat and have a rating of at least 8 and are older than 40**: - Join the `Sailors`, `Reserves`, and `Boats` relations. - Apply selection to filter for blue boats, ratings ≥ 8, and age > 40. - Project the sailor names.2. For **finding sailors who reserved only blue boats**: - Identify the sailors who booked blue boats. - Ensure that the identified sailors did not reserve boats of other colors

Question 2: Relational Model / Relational Algebra Consider the following schema, Sailors(sid: integer, sname: string, rating: integer, age: real); Boats(bid: integer, bname: string, color: string); Reserves(sid: integer, bid: integer, day: date). Symbols you may need: n --U -- o -- I -- -P You use anything that we covered in the slides. 1. Find the names of sailors who reserved a blue boat, have rating at least 8 and older than 40. 2. Find the names of sailors who reserved only blue boats. 3. Find the names of sailors who reserved at least two boats. (Similar to our example of “Find the students who earned at least two As")

Question 2: Relational Model / Relational Algebra Consider the following schema, Sailors(sid: integer, sname: string, rating: integer, age: real); Boats(bid: integer, bname: string, color: string); Reserves(sid: integer, bid: integer, day: date). Symbols you may need: n --U -- o -- I -- -P You use anything that we covered in the slides. 1. Find the names of sailors who reserved a blue boat, have rating at least 8 and older than 40. 2. Find the names of sailors who reserved only blue boats. 3. Find the names of sailors who reserved at least two boats. (Similar to our example of “Find the students who earned at least two As")

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

See similar textbooks

Similar questions

QUESTION 14 Consider the database schema below for cities in countries. A country have many cities, and the same city name can be found in different countries. Country (ID: integer, Name: String (unique), SN: serialNumber (int)(unique)) City (serialNo: integer (unique, not null), CountryID: Integer, CityName: String, Population: integer) The same country (ID , name) can be added twice in Country relation with different SN? No, violates entity Integrity constraint No, violates referential integrity constraint. No, violates key constraint. Yes. No, violates domain constraints.
If you sell a house more than once, it is treated as different "property" for each sale. Draw an entity-relationship diagram and write a database design outline. Q2. Law Office: You are trying to automate the records for your uncle's law firm. Multiple attorneys work for the firm, and for each of them you want to store their first name, last name, date hired, hourly billing rate, and date promoted to partner (blank if the attorney is not a partner). Each attorney has multiple cases, which is identified by a unique "docket number". Each case has a name and description, is worked on by only one attorney, and involves a single client. For each client, you want to store a first name, last name, middle name, phone number, address, city, state, and zip code (assume you do not have a zip-code table). Finally, you want to keep track of the billable hours spent on each case. For a single case, this comprises information that looks like Hours Billed Date 2/24/2005 Description Prepare brief…
Given the database schema with the following relations: STUDENT (id_stud, name_stud) LECTURER (id_lect, name_lect) SUBJECT (id_subject, id_lect, name_subject, credits, id_room) ROOM (id_room, no_room) ENROLL (id_stud, id_subject) Create an algebraic relation for: a. Displays all names of lecturers who teach the subject with a total of 4 credits b. Displays all no_room with the student name "Eko" c. Displays all data in the form of student id, student name, name of the course followed and the name of the lecturer who taught the subject name "Database" From the database schema and the questions above, create an appropriate SQL query for each of these statements above.
Produce a relational schema diagram that corresponds to the linked ER diagram for a database for the television show Saturday Night Live (SNL). Your relational schema diagram should include primary and foreign keys. Often-times in database system development, requirements will change after the conceptual data model has been drafted: in your rela- tional schema diagram, add the following three additional attributes: attribute “birth.date" for the relation schema Host; attribute “start.date" for the relation schema Writer; and attribute “salary" for relation schema Cast Member. Please refer back to the requirements in Question 6, for additional details that may constrain the design of the relational schema model. Use the tool linked to create an image. Hints: please carefully note that "rerun date", “address", and “phone" are multi-valued attributes; how would those be depicted in the relational schema diagram? Also, please carefully note the many-to-many relationships; how would those…
Consider the following relations for a simple airport databas Hangars (hangNo, capacity, location, status) AirplaneTypes (Model, capacity, weight) Airplanes (regNo, model, hangNO) Owners (owner, name, address, phone, ssn) Owns (regNo, ownID, startedDate) There are four foreign keys for this database: 1. The attribute hangNo of the relation Airplanes that references the relation Hangars, 2. The attribute model of the relation Airplanes that references the relation AirplaneTypes, 3. The attribute regNo of the relation Owns that references the relation Airplanes, and 4. The attribute ownID of the relation Owns that references the relation Owner. Q1: Write SQL statements to define the above relation Hangars. You should choose a suitable data type and/or daya size for each column and be sure to declare appropriate integrity constraint(s). Q2. Which of the following SQL statements is used to define the above relation Airplanes? Ensure the data type and size for each attribute are…
Here is the database design for the personnel data: employee(id, name, address) employeeMap(id, confidentialId) empSalary(confidentialId, salary) The role 'Clerk' would be granted SELECT, UPDATE, DELETE to employee table and granted SELECT to empSalary table. While the clerk can see salary information for any statistical analysis (e.g. average salary computation), he has no idea which employee the salary is for. The role 'Administrator' is granted rights on all three tables; using the confidentialId in the employeeMap table, she has access to salary data for individual employees too. A SQL query that the administrator can use to access all employee fields is: select e.id, e.name, e.address, es.salary from employee e inner join employeeMap m on e.id = m.id inner join empSalary s on m.confidentialId = s.confidentialId; Can you draw a database schema?
Consider the following schema: Publisher (name, phone, city), PK: name. Book (ISBN, title, year, published_by, previous_edition, price), PK: ISBN, FK: published_by refs Publisher, previous_edition refs Book. Author (SSN, first_name, last_name, address, income), PK: SSN. Write (aSSN, bISBN), PK: (aSSN, bISBN), FK: aSSN refs Author, bISBN refs Book. Editor (SSN, first_name, last_name, address, salary, works_for, book_count), PK: SSN, FK: works_for refs Publisher. Edit (eSSN, bISBN), PK: (eSSN, bISBN), FK: eSSN refs Editor, bISBN refs Book. Author_Editor (aeSSN, hours), PK: aeSSN, FK: aeSSN refs Author, aeSSN refs Editor. Give SQL statements for the following plain English language queries based on the above schema.
Swing Jazz Club ERD Problem Follow the Simple Procedure for ERD diagramming to design an ERD using the following user provided information. Remember the ERD will eventually turn into the design for a database from a top down view. Make sure you resolve any many to many conflicts. Label an identifier or primary key and all pertinent attributes given. If an attribute is not readily apparent from the user information, then make one up that makes sense for the particular entity. Therefore, all entities should end up with at least an identifier and another attribute that makes sense. You may use any of the approaches shown by the book, though the ER-Model and Crow’s foot are the most common. Make sure you show entities, relationships, cardinality, and optionality. Swing Jazz Club The Swing Jazz Club teaches swing and jazz dancing and offers both private and group lessons. Swing Jazz charges $60 dollars per hour for a private lesson and $10 dollars per hour for a group lesson.…
WRITE THE OF MYSQL IN PYTHON, JUST ANSWER THE 2ND QUESTION BY LOOKING AT THE FIRST QUESTION Create database and tables as given below by using Python. (a) Market database (b) Vendor: vendor id integer, vendor name varchar, license start date, license end date (c) Item:itemidinteger,itemnamevarchar,itemtypevarchar, previous price float, last sold date date (d) Auction: auction id integer, vendor id integer, item id integer, price float Choose primary and foreign keys depending on the relations in Market database design. Create arrays of at least 5 di↵erent records. Use these arrays to populate each table in the database.
Giving the following schema for a supermarket database, specify the domain constrains for each attribute. CUSTOMERS (CustomerID , First_Name, Last_Name) EMPLOYEES (EmployeeID, Name, Email, PhoneNo) INVOICES( InvoiceID, Amount_Paid, Invoice_Date)
You have an application domain that consists of Cities, Towns, and Neighborhoods. A City has a name, zip code, state, and a country. A Town has a name, zip code, state, and country. A Neighborhood has a name, coordinate, and population. Using a relational model, what are Students, Courses, and Sections called? Select one: a. Attributes b. Constraints c. Entities d. Relations
QUESTION 4 Consider the following database schema for a library. Book (BookID:int, BookTitle:string(unique), Author:string, publisher:string) Borrowing-Record (BookID: int, CustomerCPR: int, Date: date, Time: time, Price: double) Customer (CPR:int, name: String) In Borrowing-Record, there are three primary keys? O True False