Exercise 2.1 Explain the accompanying terms quickly trait, space, e.pdf
- 1. Exercise 2.1 Explain the accompanying terms quickly: trait, space, element, relationship, element set, relationship set, one-to-numerous relationship, numerous to-numerous relationship, interest limitation, cover requirement, covering imperative, feeble element set, total, what's more, part marker. Answer 2.1 No answer gave yet. Exercise 2.2 A college database contains data about teachers (recognized by government managed savings number, or SSN) and courses (recognized by courseid). Teachers show courses; each of the accompanying circumstances concerns the Teaches relationship set. For every circumstance, draw an ER outline that portrays it (expecting that no further limitations hold). 1. Educators can instruct the same course in a few semesters, and every offering must be recorded. 2. Educators can instruct the same course in a few semesters, and just the most late such offering should be recorded. (Accept this condition applies taking all things together consequent inquiries.) 3. Each educator must show some course. 4. Each teacher instructs precisely one course (no all the more, no less). 5. Each teacher instructs precisely one course (no all the more, no less), and each course must be educated by some educator. 6. Presently assume that specific courses can be instructed by a group of teachers together, in any case, it is conceivable that nobody teacher in a group can educate the course. Model this circumstance, presenting extra element sets and relationship sets if important. Answer 2.2 Answer overlooked. 5 6 Chapter 2 Exercise 2.3 Consider the accompanying data around a college database: Educators have a SSN, a name, an age, a rank, and an examination claim to fame. Ventures have a task number, a supporter name (e.g., NSF), a beginning date, an finishing date, and a financial plan. Graduate understudies have a SSN, a name, an age, and a degree program (e.g., M.S. on the other hand Ph.D.). Every task is overseen by one educator (known as the venture's important specialist). Every venture is dealt with by one or more educators (known as the undertaking's co-agents).
- 2. Teachers can oversee and/or chip away at different activities. Every task is chipped away at by one or more graduate understudies (known as the task's exploration collaborators). At the point when graduate understudies chip away at a venture, an educator must manage their work on the task. Graduate understudies can deal with different tasks, in which case they will have a (possibly diverse) chief for every one. Offices have a division number, an office name, and a principle office. Offices have an educator (known as the executive) who runs the division. Teachers work in one or more divisions, and for every office that they work in, a period rate is connected with their occupation. Graduate understudies have one noteworthy division in which they are chipping away at their degree. Every graduate understudy has another, more senior graduate understudy (known as a understudy counsel) who exhorts him or her on what courses to take. Outline and draw an ER chart that catches the data about the college. Utilize just the fundamental ER model here, that is, elements, connections, and characteristics. Be beyond any doubt to show any key and investment imperatives. Answer 2.3 The ER chart is appeared in Figure 2.1. Exercise 2.4 An organization database needs to store data about representatives (recognized by ssn, with compensation and telephone as characteristics); divisions (distinguished by dno, with dname and spending plan as properties); and offspring of workers (with name and age as traits). Representatives work in offices; every division is overseen by an The Entity-Relationship Model 7 work_in Manages venture pid support start_date end_date spending plan Dept Work_dept Runs office dname dno Professor ssn age rank strength Major Work_proj Graduate Advisor senior graduate ssn pc_time age ssn deg_prog name Supervises Figure 2.1 ER Diagram for Exercise 2.3 8 Chapter 2 worker; a tyke must be recognized remarkably by name when the guardian (who is an worker; expect that stand out guardian works for the organization) is known. We are definitely not intrigued by data around a tyke once the guardian leaves the organization. Draw an ER chart that catches this data. Answer 2.4 Answer overlooked. Exercise 2.5 Notown Records has chosen to store data about performers who
- 3. perform on its collections (and in addition other organization information) in a database. The organization has shrewdly contracted you as a database planner (at your typical counseling charge of $2,500/day). Every performer that records at Notown has a SSN, a name, a location, and a telephone number. Ineffectively paid artists regularly have the same location, and no address has more than one telephone. Every instrument that is utilized as a part of tunes recorded at Notown has a name (e.g., guitar, synthesizer, woodwind) and a musical key (e.g., C, B-level, E-level). Every collection that is recorded on the Notown name has a title, a copyright date, a position (e.g., CD or MC), and a collection identifier. Every melody recorded at Notown has a title and a creator. Every performer may play a few instruments, and a given instrument might be played by a few performers. Every collection has various tunes on it, however no tune may show up on more than one collection. Every melody is performed by one or more artists, and an artist may play out a number of melodies. Every collection has precisely one performer who goes about as its maker. An artist may produce a few collections, obviously. Plan a reasonable composition for Notown and draw an ER outline for your construction. The taking after data portrays the circumstance that the Notown database must model. Make certain to show all key and cardinality limitations and any presumptions that you make. Recognize any limitations that you can't catch in the ER outline and quickly clarify why you couldn't express them. Answer 2.5 The ER graph is appeared in Figure 2.2. The Entity-Relationship Model 9 ssn Musicians name Album copyrightDate speed albumIdentifier dname Instrument instrId key songId Songstitle suthor Plays Appears Perform Producer title address Home Lives Place Telephone phone_no Figure 2.2 ER Diagram for Exercise 2.5 10 Chapter 2 Exercise 2.6 Computer Sciences Department regular fliers have been whining to Dane County Airport authorities about the poor association at the air terminal. As a result, the authorities have concluded that all data identified with the air terminal ought to be sorted out utilizing a DBMS, and you've been employed to outline the database. Your first undertaking
- 4. is to sort out the data about every one of the planes that are positioned and kept up at the air terminal. The applicable data is as per the following: Each plane has an enlistment number, and every plane is of a particular model. The air terminal suits various plane models, and every model is distinguished by a model number (e.g., DC-10) and has a limit and a weight. Various professionals work at the air terminal. You have to store the name, SSN, address, telephone number, and pay of every professional. Every professional is a specialist on one or more plane model(s), and his or her ability may cover with that of different professionals. This data about specialists should likewise be recorded. Movement controllers must have a yearly medicinal examination. For every movement controller, you should store the date of the latest exam. All airplane terminal workers (counting specialists) have a place with a union. You should store the union participation number of every worker. You can accept that each representative is exceptionally recognized by the government disability number. The air terminal has various tests that are utilized intermittently to guarantee that planes are still airworthy. Every test has a Federal Aviation Administration (FAA) test number, a name, and a most extreme conceivable score. The FAA requires the air terminal to monitor every time that a given plane is tried by a given specialist utilizing a given test. For every testing occasion, the data required is the date, the quantity of hours the specialist spent doing the test, and the score that the plane got on the test. 1. Draw an ER graph for the air terminal database. Make certain to show the different qualities of every element and relationship set; likewise indicate the key and interest imperatives for every relationship set. Determine any vital cover and covering requirements too (in English). 2. The FAA breezes through a direction that tests on a plane must be led by a professional who is a specialist on that model. How might you express this requirement in the ER chart? On the off chance that you can't express it, clarify quickly. Exercise 3.11 Suppose that we have a ternary relationship R between entity sets A, B, and C such that A has a key constraint and total participation and B has a key constraint; these are the only constraints. A has attributes a1 and a2, with a1 being the key; B and C are similar. R has no descriptive attributes. Write SQL statements that create tables corresponding to this information so as to capture as many of the constraints as possible. If you cannot capture some constraint, explain why. Answer 3.11 The following SQL statement creates Table A: CREATE TABLE A ( a1 CHAR(10), a2 CHAR(10), PRIMARY KEY (a1) ) Tables B and C are similar to A. CREATE
- 5. TABLE R ( a1 CHAR(10), b1 CHAR(10) NOT NULL , c1 CHAR(10) , PRIMARY KEY (a1), UNIQUE (b1) FOREIGN KEY (a1) REFERENCES A, FOREIGN KEY (b1) REFERENCES B ) FOREIGN KEY (c1) REFERENCES C ) We cannot capture the total participation constraint of A in R. This is because we cannot ensure that every key a1 appears in R without the use of checks. Exercise 3.12 Consider the scenario from Exercise 2.2 where you designed Solution Exercise 2.1 Explain the accompanying terms quickly: trait, space, element, relationship, element set, relationship set, one-to-numerous relationship, numerous to-numerous relationship, interest limitation, cover requirement, covering imperative, feeble element set, total, what's more, part marker. Answer 2.1 No answer gave yet. Exercise 2.2 A college database contains data about teachers (recognized by government managed savings number, or SSN) and courses (recognized by courseid). Teachers show courses; each of the accompanying circumstances concerns the Teaches relationship set. For every circumstance, draw an ER outline that portrays it (expecting that no further limitations hold). 1. Educators can instruct the same course in a few semesters, and every offering must be recorded. 2. Educators can instruct the same course in a few semesters, and just the most late such offering should be recorded. (Accept this condition applies taking all things together consequent inquiries.) 3. Each educator must show some course. 4. Each teacher instructs precisely one course (no all the more, no less). 5. Each teacher instructs precisely one course (no all the more, no less), and each course must be educated by some educator. 6. Presently assume that specific courses can be instructed by a group of teachers together, in any case, it is conceivable that nobody teacher in a group can educate the course. Model this circumstance, presenting extra element sets and relationship sets if important. Answer 2.2 Answer overlooked. 5 6 Chapter 2 Exercise 2.3 Consider the accompanying data around a college database: Educators have a SSN, a name, an age, a rank, and an examination claim to fame.
- 6. Ventures have a task number, a supporter name (e.g., NSF), a beginning date, an finishing date, and a financial plan. Graduate understudies have a SSN, a name, an age, and a degree program (e.g., M.S. on the other hand Ph.D.). Every task is overseen by one educator (known as the venture's important specialist). Every venture is dealt with by one or more educators (known as the undertaking's co-agents). Teachers can oversee and/or chip away at different activities. Every task is chipped away at by one or more graduate understudies (known as the task's exploration collaborators). At the point when graduate understudies chip away at a venture, an educator must manage their work on the task. Graduate understudies can deal with different tasks, in which case they will have a (possibly diverse) chief for every one. Offices have a division number, an office name, and a principle office. Offices have an educator (known as the executive) who runs the division. Teachers work in one or more divisions, and for every office that they work in, a period rate is connected with their occupation. Graduate understudies have one noteworthy division in which they are chipping away at their degree. Every graduate understudy has another, more senior graduate understudy (known as a understudy counsel) who exhorts him or her on what courses to take. Outline and draw an ER chart that catches the data about the college. Utilize just the fundamental ER model here, that is, elements, connections, and characteristics. Be beyond any doubt to show any key and investment imperatives. Answer 2.3 The ER chart is appeared in Figure 2.1. Exercise 2.4 An organization database needs to store data about representatives (recognized by ssn, with compensation and telephone as characteristics); divisions (distinguished by dno, with dname and spending plan as properties); and offspring of workers (with name and age as traits). Representatives work in offices; every division is overseen by an The Entity-Relationship Model 7 work_in Manages venture pid support start_date end_date spending plan Dept Work_dept Runs office dname dno Professor ssn age rank strength Major Work_proj Graduate Advisor senior graduate ssn pc_time age ssn deg_prog name Supervises Figure 2.1 ER Diagram for Exercise 2.3 8 Chapter 2
- 7. worker; a tyke must be recognized remarkably by name when the guardian (who is an worker; expect that stand out guardian works for the organization) is known. We are definitely not intrigued by data around a tyke once the guardian leaves the organization. Draw an ER chart that catches this data. Answer 2.4 Answer overlooked. Exercise 2.5 Notown Records has chosen to store data about performers who perform on its collections (and in addition other organization information) in a database. The organization has shrewdly contracted you as a database planner (at your typical counseling charge of $2,500/day). Every performer that records at Notown has a SSN, a name, a location, and a telephone number. Ineffectively paid artists regularly have the same location, and no address has more than one telephone. Every instrument that is utilized as a part of tunes recorded at Notown has a name (e.g., guitar, synthesizer, woodwind) and a musical key (e.g., C, B-level, E-level). Every collection that is recorded on the Notown name has a title, a copyright date, a position (e.g., CD or MC), and a collection identifier. Every melody recorded at Notown has a title and a creator. Every performer may play a few instruments, and a given instrument might be played by a few performers. Every collection has various tunes on it, however no tune may show up on more than one collection. Every melody is performed by one or more artists, and an artist may play out a number of melodies. Every collection has precisely one performer who goes about as its maker. An artist may produce a few collections, obviously. Plan a reasonable composition for Notown and draw an ER outline for your construction. The taking after data portrays the circumstance that the Notown database must model. Make certain to show all key and cardinality limitations and any presumptions that you make. Recognize any limitations that you can't catch in the ER outline and quickly clarify why you couldn't express them. Answer 2.5 The ER graph is appeared in Figure 2.2. The Entity-Relationship Model 9 ssn Musicians name Album copyrightDate speed albumIdentifier dname Instrument instrId key songId Songstitle suthor Plays Appears Perform Producer title address Home Lives Place Telephone phone_no
- 8. Figure 2.2 ER Diagram for Exercise 2.5 10 Chapter 2 Exercise 2.6 Computer Sciences Department regular fliers have been whining to Dane County Airport authorities about the poor association at the air terminal. As a result, the authorities have concluded that all data identified with the air terminal ought to be sorted out utilizing a DBMS, and you've been employed to outline the database. Your first undertaking is to sort out the data about every one of the planes that are positioned and kept up at the air terminal. The applicable data is as per the following: Each plane has an enlistment number, and every plane is of a particular model. The air terminal suits various plane models, and every model is distinguished by a model number (e.g., DC-10) and has a limit and a weight. Various professionals work at the air terminal. You have to store the name, SSN, address, telephone number, and pay of every professional. Every professional is a specialist on one or more plane model(s), and his or her ability may cover with that of different professionals. This data about specialists should likewise be recorded. Movement controllers must have a yearly medicinal examination. For every movement controller, you should store the date of the latest exam. All airplane terminal workers (counting specialists) have a place with a union. You should store the union participation number of every worker. You can accept that each representative is exceptionally recognized by the government disability number. The air terminal has various tests that are utilized intermittently to guarantee that planes are still airworthy. Every test has a Federal Aviation Administration (FAA) test number, a name, and a most extreme conceivable score. The FAA requires the air terminal to monitor every time that a given plane is tried by a given specialist utilizing a given test. For every testing occasion, the data required is the date, the quantity of hours the specialist spent doing the test, and the score that the plane got on the test. 1. Draw an ER graph for the air terminal database. Make certain to show the different qualities of every element and relationship set; likewise indicate the key and interest imperatives for every relationship set. Determine any vital cover and covering requirements too (in English). 2. The FAA breezes through a direction that tests on a plane must be led by a professional who is a specialist on that model. How might you express this requirement in the ER chart? On the off chance that you can't express it, clarify quickly.
- 9. Exercise 3.11 Suppose that we have a ternary relationship R between entity sets A, B, and C such that A has a key constraint and total participation and B has a key constraint; these are the only constraints. A has attributes a1 and a2, with a1 being the key; B and C are similar. R has no descriptive attributes. Write SQL statements that create tables corresponding to this information so as to capture as many of the constraints as possible. If you cannot capture some constraint, explain why. Answer 3.11 The following SQL statement creates Table A: CREATE TABLE A ( a1 CHAR(10), a2 CHAR(10), PRIMARY KEY (a1) ) Tables B and C are similar to A. CREATE TABLE R ( a1 CHAR(10), b1 CHAR(10) NOT NULL , c1 CHAR(10) , PRIMARY KEY (a1), UNIQUE (b1) FOREIGN KEY (a1) REFERENCES A, FOREIGN KEY (b1) REFERENCES B ) FOREIGN KEY (c1) REFERENCES C ) We cannot capture the total participation constraint of A in R. This is because we cannot ensure that every key a1 appears in R without the use of checks. Exercise 3.12 Consider the scenario from Exercise 2.2 where you designed