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Thursday, November 29, 2012

cs403 mid spring 2010



MIDTERM EXAMINATION

Spring 2010

CS403- Database Management Systems (Session - 6)


Q-  Which of the following constraints enforces entity integrity? PRIMARY KEY
FOREIGN KEY
CHECK
NOT NULL

Q- Which of the following statements is correct? PK can have NULL
PK in a relation is a key in some other relation
PK can be composite
PK must be selected from the list of secondary keys

Q- Which one of the following E-R diagrams most correctly represents the relationship between Student and Grade entities?
  
Q- Which of the following most certainly implies the need for an entire table to implement?

A binary relationship
A ternary relationship
A recursive relationship
An identifying relationship

Q- A database system allows the following EXCEPT
management and control of data towards an efficient working of an organisation.
more critical functions in organisations to be computerised and the need to keep a large volume of data available in an up to the minute current state increased.
any user to access all its data.
integration of data across multiple applications into a single application.

Q- Which of the following enforces a relation into 1st normal form?

The domain of attribute must include only atomic values.
Every non-key attribute is fully functionally dependent on primary key
non-key attribute is non-transitively dependent on primary key.
Every non-key attribute is partially dependent on super key

Q- Consider the following set of functional dependencies (FDs) on the following relational schema.
Emp_No -> {Ename, Bdate, Address, Dept_No}
Dept_No -> {Dname, Mgr_No}
The additional FD which can be inferred from the above set of FDs is
Emp_No -> {Dname, Mgr_No} Emp_Name -> Dept_No . Emp_Name -> Dept_Name . Emp_Name, Dept_No -> Mgr_No .

Q- Select the correct statement about the ANSI/SPARC architecture.

The conceptual level is a level of indication between the internal level and the external level.
The internal level in a database system will definitely be relational. Tuka uncle lagao…
Any given database has many conceptual schemas and one physical schema, but it has only one external schemas.
The external level is not concerned with individual user perceptions, while the conceptual level
is concerned with a community user perception.

Q- Which of the following is a feature of PRIMARY KEY constraint unique identifier for a row within a database table.

allow any actions that would destroy links between tables limit the values that can be placed in a column.
enforces that the column will only accept null values. Q- Structural constraints of a relationship type refer to

identifying the owner entity type relevant to a given entity type




the

whether the existence of an entity depends on it being related to another entity via

relationship type.
the role that a participating entity from the entity type plays in each relationship instance.
the constraints applicable in granting access to tables, columns and views in a database
schema.

Q- Which of the following is true about relational schema?
The sequence of columns is significant
The sequence of rows is significant.
Contains only derived attributes.
Values are atomic.







Q- A unary ternary binary weak

relationship exists when an association is maintained within a single entity.



Q- Which of the following is a correct way to implement one-to-many relationship while designing tables?

by splitting the data into two tables with primary key and foreign key relationships.
using a junction table with the keys from both the tables forming the composite primary key of the junction table.
by splitting each table into three
as a single table and rarely as two tables with primary and foreign key relationships.

Q- Identify the correct statement.

Entity integrity constraints specify that primary key values can be composite.
Entity integrity constraints are specified on individual relations.
Entity integrity constraints are specified between weak entities.
When entity integrity rules are enforced, a tuple in one relation that refers to another relation must refer to an existing tuple.



Q- A software package designed to store and manage databases
Database
DBMS
Data model
Data


Q- Who is responsible for authorizing access to the database, for coordinating and monitoring its use?
Select correct option:
Database Designer
Database Administrator
End User
Application Programmer


Q- Consider the following relation R and its sample data. (Consider that these are the only tuples for the given relation)


Q- Which of the following statements is NOT correct?

The functional dependency (EmpNo, DeptNo) -> ProjNo holds over R.
The functional dependency EmpNo -> DeptNo holds over R.
The functional dependency ProjNo -> DeptNo holds over R.
The functional dependency (EmpNo, ProjNo) -> DeptNo holds over R.



Q- Which feature of database provides conversion from inconsistent state of DB to a consistent state ensuring minimum data loss?
Select correct option:
User accessible catalog
Data processing
Recovery service
Authorization service

Q- Consider the given relations Student and Instructor as given below. Please note that
Fname and Lname also denote the First Name and Last Name respectively.


Which of the following statements is correct with respect to the two relations given above?

The two relations are not union-compatible since their attribute names differ.
The set operations such as CARTESIAN PRODUCT and DIVISION can be applied on
these
two relations.
To find out those students who work as instructors, it is necessary to perform the operation
Student ∩ Instructor.
To find out the students who are not instructors, it is necessary to perform the operation
Student ÷ Instructor.


Q- A candidate key that does not have a null value and is selected to uniquely identify all other attribute values in any given row is called a     .
Select correct option:
superkey candidate key primary key secondary key

Q- What is the significance of normalization? Q- Define Relationship.

Q- What is the basic function of a DML Compiler? Q- Define primary key and give one example.

Q- What do you know about Insertion anomaly?

Q- Define the first normal form.\


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