2. For the following questions, please identify the candidate keys of the given relations. You need to show the process to justify your answers. a) The given relation is R1(ABCDE). The given dependencies are A B B-E C-D b) The given relation is R2(ABCDE). The given dependencies are AB-BCDE BC ACE D-E

2. For the following questions, please identify the candidate keys of the given relations. You need to show the process to justify your answers. a) The given relation is R1(ABCDE). The given dependencies are A B B-E C-D b) The given relation is R2(ABCDE). The given dependencies are AB-BCDE BC ACE D-E

Database Systems: Design, Implementation, & Management

12th Edition

ISBN:9781305627482

Author:Carlos Coronel, Steven Morris

Publisher:Carlos Coronel, Steven Morris

Chapter8: Advanced Sql

Section: Chapter Questions

Problem 18RQ

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Normalize the following given data to 1/2/3 NF. State the relations schema after everynormalization.
Given the relations a(name, address, title) and b(name, address, salary), show how to express a natural full outer join b using the full outer-join operation with an on condition rather than using the natural join syntax. This can be done using the coalesce operation. Make sure that the result relation does not contain two copies of the attributes name and address and that the solution is correct even if some tuples in a and b have null values for attributes name or address.
Question 1 Suppose you are given a relation R = (A, B, C, D, E) with the following functional dependencies: C, E >D D-B CA a) Find all candidate keys. b) If the relation is not in BCNF, decompose it until it becomes BCNF, At each step, identify a new relation, decompose and re-compute the keys and the normal forms they satisfy.
For relation (R), its attributes and its functional dependencies (F): R(A, B, C, D, E) C D → B A → D E → C 1. Decompose the above relation using the Boyce-Codd Normal Form (BCNF) decomposition. 2. What is the key for the relation R?
under what three circumstances does it become necessary to generate a surrogate key in place of the main key of a relation?
The text states that you can argue that “the only reason for having relations is to store instances of functional dependencies.” Explain, in your own words, what this means
If there are more than one possible candidate keys, provide some instances of relations that have more than one.
Consider the following relation: r (A1, A2, A3). For all the states of the relation, the result of Query #1 is always the same as that of Query #2. Specify the primary key of the relation r (30 points); Explain why it must be the primary key.Query #1: sr1.A2=r2.A2 Ù r1.A1=r2.A1 (rr1 (r) ´ rr2 (r))Query #2: select *from r as r1, r as r2where r1.A1=r2.A1
Suppose you have a Relation that has an atomic Primary Key and noRepeating Groups. All non-key columns are functionally dependent on the Primary Key, but it has a Transitive Functional Dependency. How would you resolve this Transitive Functional Dependency? you would create a 1:M relationship between the initial table and a new table and place the columns that are Transitively Functionally Dependent on the many side. You would move the columns that are Transitively Functionally Dependent to a parent table. The column they were Transitively Functionally Dependent on serves as the Foreign Key to the parent table Transitive Functional Dependencies can only exist with a Composite Primary Key and the, therefore, can;t exist in the table as it has an atomic Primary Key. You would move the column that are Transitively FUnctionally Dependent to a child table. The column they were Transitively Functionally Dependent on serves as the Primary Key to the child Table
Here's a relation (R), its attributes and its functional dependencies (F): R(A, B, C, D, E, F, G) BC -> DG CD -> F FG -> A 1. compute the closure of {ACD}+ 2. compute the closure of {F}+ 3. what are the keys of R?
For developing our queries, we will be using the following relational schema: Student(SID, name, username, major) Course(cname, description, department, weight) Offering(OID, cname, year, term, duration) Enrolled(SID, OID, grade) A course relation is the generic description of a course which is offered by a department. The offering relation is the specific instance of a course being taught in a given term, and is the entity which will be associated with the student enrollment. Students are enrolled in these offerings and achieve a mark. Express each of following queries in Relational Algebra: | Write a relational algebra query which will list the cname and description of all the courses which are being offering in the Fall 2018 term. 2 Write a relational algebra query which will list the name of all the students who have earned 60% in both 'COSC2P12' and 'COSC2P13'.
Transform the following E-R diagram into relations

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