F.Y.B.Sc. Computer Science Semester I (75:25) Regular Solution Set USCS104 DBMS, November 2017 QP Code: (23/11/2017)

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1 F.Y.B.Sc. Computer Science Semester I (75:25) Regular Solution Set USCS104 DBMS, November 2017 QP Code: (23/11/2017) Q. 1 Attempt All. (15M) (a) Multiple Choice Questions 1. Row 2. CITY, ID 3. Sigma(Greek) 4. None of the above 5. No partial functional dependencies exist (b) Fill in the blanks. 1. Data item 2. 4NF 3. Intersect 4. Three levels 5. Structured Query language (c) Short Answers 1. Marks and % ; age and DOB 2. σp(r) 3. Will print the date which is entered in the date() command. 4. removing the leading space character 5. A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data. Q. 2 Attempt the following (Any THREE) (15M) (a) State the drawback of traditional file processing systems. Separated and Isolated Data: 2. Duplication of data: 3. Data Dependence: (b) 4. Difficulty in representing data from the user's view: 5. Data Inflexibility: 6. Incompatible file formats: 7. Data Security. 8. Transactional Problems. 9. Concurrency problems. [any 5 ; each 1 marks] Show an E-R diagram illustrating the use entity sets listed. Galleries keep information about artists, their names (which are unique), birthplaces, age,and style of art. For each piece of artwork, the artist, the year it was made, its unique title, its type of art (e.g., painting, lithograph, sculpture, photograph), and its price must be stored. Pieces of artwork are also classified into groups of various kinds, for example, portraits, still lifes, works by Picasso, or works of the 19th century; a given piece may

2 belong to more than one group. Each group is identified by a name (like those justt given) thatt describes the group. Finally, galleries keep information about customers. For each customer, galleries keep that person s unique name, address, total amount of dollars spent in the gallery (very important!), and the artistss and groups of art that the customer tends to like. [correct ER 5 marks] (c) List and explain List and explain different database users.. Application Programmers are computerprofessionals interacting with the system through DML calls embedded in a program written in a host language (e.g. C, PL/1, Pascal): These programs are called Application Programs. The DML Precompiled converts DML calls (prefaced by a special character like $, #, etc.) to normal procedure calls in a host language. The host language compiler then generates the object code. Some special types of programmin ng languages combine Pascal-like control structures with control structures for the manipulation of a database. These are sometimes called Fourth-Generation Languages. They often include features which too generate forms and display data. Sophisticated Users interact with the system without writing programs :They form requests by writing queries in a database queryy language. These are submitted to a query processor that breaks a DML statement down into instructions for the database manager module. Specialized Users are sophisticated userss writing special database application programs. These may be CADD systems, knowledge-basedd and expert systems, complex data systemss (audio/video), etc. Naive Users are unsophisticated users who interact with the system by using permanent application programs (e. g. automated teller machine). [each 1 marks]

3 (d) (e) (f) What do you mean by Null constraint, Check constraint? Discuss with suitable example? The CHECK constraint is used to limit the value range that can be placed in a column. If you define a CHECK constraint on a single column it allows only certain values for this column. If you define a CHECK constraint on a table it can limit the values in certain columns based on values in other columns in the row. CREATE TABLE Persons ( ID int NOT NULL, LastNamevarchar(255) NOT NULL, FirstNamevarchar(255), Age int CHECK (Age>=18) ); CREATE TABLE CUSTOMERS( ID INT NOT NULL, NAME VARCHAR (20) NOT NULL, AGE INT NOT NULL, ADDRESS CHAR (25), SALARY DECIMAL (18,2), PRIMARY KEY (ID) ); [each 2.5 marks] List and explain different types of mapping cardinalities. 1:1 1:M M:M M:1 With suitable examples. Draw an ER diagram showing movie ticket management system. [Assume suitable data and state them clearly.] [correct diagram 5 marks] Q. 3 Attempt the following (Any THREE) (15M) (a) Giving 2 examples explain 1 NF. First Normal Form (1NF) A relation is said to be in 1NF if it contains no non-atomic values and each row can provide a unique combination of values. The above table in UNF can be processed to create the following table in 1NF. Emp-Name Month Sales Bank-Id Bank-Name Emp-Id E01 AA Jan 1000 B01 SBI E01 AA Feb 1200 B01 SBI E01 AA Mar 850 B01 SBI E02 BB Jan 2200 B02 UTI E02 BB Feb 2500 B02 UTI E03 CC Jan 1700 B01 SBI

4 E03 CC Feb 1800 B01 SBI E03 CC Mar 1850 B01 SBI E03 CC Apr 1725 B01 SBI As you can see now, each row contains unique combination of values. Unlike in UNF, this relation contains only atomic values, i.e. the rows cannot be further decomposed, so the relation is now in 1NF. [any 2 example ; each 2.5 marks] (b) (c) (d) Explain any 3 aggregate functions with examples. AVG function : SELECT AVG(buyPrice) average_buy_price FROM products COUNT function : select COUNT(*) AS Total FROM products SUM function MAX function Min [any 3; 5 marks] Discuss cross product, union operations from relational algebra with suitable example. Union Operation ( ) It performs binary union between two given relations and is defined as r s = { t t r or t s} Notion r U s Where r and s are either database relations or relation result set (temporary relation). For a union operation to be valid, the following conditions must hold r, and s must have the same number of attributes. Attribute domains must be compatible. Duplicate tuples are automatically eliminated. author (Books) author (Articles) Output Projects the names of the authors who have either written a book or an article or both. Cartesian Product (Χ) Combines information of two different relations into one. Notation r Χ s Where r and s are relations and their output will be defined as r Χ s = { q t q r and t s} σauthor = 'tutorialspoint'(books Χ Articles) [[each 2.5] Perform following using mysql Create a table student (rollno,name,address) rollno is PK. Insert 2 records Delete a record whose rollno is 3. Find a record whose name starts with a. [correct query 5 marks]

5 (e) How to perform commit and rollback operation give example to support your answer. (f) Construct tables from the above ER diagram. [Assume suitable mapping cardinalities and mention them. ] Correct tables 5 marks Q. 4 Attempt the following (Any THREE) (a) Explain the concept of functional dependency withh suitable example. A functional dependency is an association between two attributes of the same relationaldatabase table. One of the attributes is called the determinant and the other attribute is calledthe determined. For each value of the determinant theree is associated one and only one valueof the determined. If A is the determinant and B is the determined then we say that A functionally determines B and graphically represent this as A -> B. The symbols A à B can also be expressed as B is functionally determined by A. Example (15)) Since for each value of A there is associated one and only one value of B. Example

6 Since for A = 3 there is associated more than one value of B. Functional dependency can also be defined as follows: An attribute in a relationall model is said to be functionally dependent on another attribute in the table if it can take only one value for a given value of the attribute upon which it is functionally dependent. [5 marks] (b) Describe the process of creating user in mysql. To login as another user first we createe a new userr and assign all privileges to that user. Open mysql command prompt and check all userss use following query. mysql> select user, host from mysql.user; user host % amol % bharat % bhaskar % ram root % % localhost root localhost rows in set (0.00 sec) To find username and host name we can also use following query. mysql> select user(); user() root@localho ost row in set (0. 00 sec) To create a new user mysql> create user mahi@ localhost IDENTIFIED BY 'mm'; Query OK, 0 rows affected (0.00 sec) It indicates that the mahi is created and they hv privileges like root whichh are Identified by

7 mm indicates that it s a password for the user. Set permissions to a user mahi. mysql>grant all privileges on *.* to mahi@localhost; Query OK, 0 rows affected (0.00 sec) Above query will provide all grants to user mahi. mysql> grant select, create on test.* to rahul@localhost ; Query OK, 0 rows affected (0.01 sec) If you want to provide specific grants to user then the above query can be used. Here you have given permission only for select and create. To logged in as user mahi ; open command prompt by typing command cmd Syntax : Mysql u user_name -p [5 for correct answer] (c) Write a short note on how to create a view with suitable example. View is a data object which does not contain any data. Contents of the view are the resultant of a base table. They are operated just like base table but they don t contain any data of their own. The difference between a view and a table is that views are definitions built on top of other tables (or views). If data is changed in the underlying table, the same change is reflected in the view. A view can be built on top of a single or multiple tables. select * from student; roll name dept mks raj maths 66 2 sam maths 65 3 anil maths 55 3 anjali CS 75 4 juhi CS 78 5 mona CS There exists a table called student. To create a view. mysql> create view stud_view as select roll,name,mks from student; [5 for correct answer ] (d) Perform following by assuming suitable data and database. Create a report that shows the city, company name, and contact name of all customers who are in cities that begin with "A" or "B." Sort by contact name in descending order. Create a report that shows the company name, contact name and fax number of all customers that have a fax number. Sort by company name.

8 (e) (f) select name from student where name like '%i'; [5 for correct answer] What do you mean by privilege with respect to database and its types. Discuss various types of Threats to Databases. Types of threats to database security 1. Privilege abuse: When database users are provided with privileges that exceeds their day-to-day job requirement, these privileges may be abused intentionally or unintentionally. Take, for instance, a database administrator in a financial institution. What will happen if he turns off audit trails or create bogus accounts? He will be able to transfer money from one account to another thereby abusing the excessive privilege intentionally. Having seen how privilege can be abused intentionally, let us see how privilege can be abused unintentionally. A company is providing a work from home option to its employees and the employee takes a backup of sensitive data to work on from his home. This not only violates the security policies of the organization, but also may result in data security breach if the system at home is compromised. 2. Operating System vulnerabilities: Vulnerabilities in underlying operating systems like Windows, UNIX, Linux, etc., and the services that are related to the databases could lead to unauthorized access. This may lead to a Denial of Service (DoS) attack. This could be prevented by updating the operating system related security patches as and when they become available. 3. Database rootkits: A database rootkit is a program or a procedure that is hidden inside the database and that provides administrator-level privileges to gain access to the data in the database. These rootkits may even turn off alerts triggered by Intrusion Prevention Systems (IPS). It is possible to install a rootkit only after compromising the underlying operating system. This can be avoided by periodical audit trails, else the presence of the database rootkit may go undetected. 4. Weak authentication: Weak authentication models allow attackers to employ strategies such as social engineering and brute force to obtain database login credentials and assume the identity of legitimate database users. 5. Weak audit trails: A weak audit logging mechanism in a database server represents a critical risk to an organization especially in retail, financial, healthcare, and other industries with stringent regulatory compliance. Logging of sensitive or unusual transactions happening in a database must be done in an automated manner for resolving incidents. Audit trails act as the last line of database defense. Audit trails can detect the existence of a violation that could help trace back the violation to a particular point of time and a particular user. Q. 5 Attempt the following (Any THREE) (15) (a) Consider the following entities for a hospital management system. Equipment: The main attributes are identification number, name, description of its functionalities, type, location, purchase cost, purchase date, etc. Department: The main attributes are identification number, name, address, total number of doctors, total number of nurses, etc. Doctor: The main attributes are identification number, name, address, area of specialty, current working schedule, etc.

9 Nurse: The main attributes are identification number, name, address, skills, current working schedule, etc. Patient: The main attributes are identification number, name, address, type (inpatient or outpatient), disease, etc. Room: The main attributes are room number, type (operating room, ward, etc.), capacity, description, etc. Draw ER diagram and define relationships. (b) (c) (d) (e) Write queries in relational algebra form: Find the information of name ram from student table. Select the records from student table who has marks > 60 Find all students having marks< 40 from student table. Rename student table to SST. Find name from student whose address is virar. [correct answer 5 marks; each 1 marks] Discuss avg (), max(), min() functions with suitable example. [5 for correct answer] Write a note on sub-query and provide example. A subquery is a SELECT statement that is embedded in a clause of another SELECT statement. You can build powerful statements out of simple ones by usingsubqueries. They can be very useful when you need to select rows from a table with a condition that depends on the data in the table itself. SELECT ename FROM EMP WHERE sal> ( SELECT sal FROM emp WHERE empno=7566); [5 for correct answer] Define the terms data, information, entity, attribute, relationship. [each 1 marks]

Homework 2: E/R Models and More SQL (due February 17 th, 2016, 4:00pm, in class hard-copy please)

Virginia Tech. Computer Science CS 4604 Introduction to DBMS Spring 2016, Prakash Homework 2: E/R Models and More SQL (due February 17 th, 2016, 4:00pm, in class hard-copy please) Reminders: a. Out of