CS403- Database Management Systems (Session - 2) Spring 2010

MIDTERM EXAMINATION
Spring 2010
CS403- Database Management Systems (Session - 2)

Question No: 1 ( Marks: 1 ) - Please choose one

Which of the following is NOT a feature of Context DFD?
► one process (which represents the entire system)


► all sources/sinks (external entities)


► data flows linking the process to the sources and sinks (external entities)


► Sub-processes (which explain and decomposed the major process into small processes)



Question No: 2 ( Marks: 1 ) - Please choose one

Which of the following is true for the relational model?
►Degree of a relation is the number of rows in a relation.


►Null value is a blank or zero value given to an attribute value when its value is inapplicable or its value is unknown.


►Complex key is a key consisting of more than one attribute.


►Constraint is a rule that restricts the values in a database.



Question No: 3 ( Marks: 1 ) - Please choose one

Which one of the following four E-R diagrams is the typical result you obtain when you initially start with an E-R diagram containing just two entities, A and C, in a Many-to-Many relationship, and then introduce an associative entity (B).
►
►
►
►







Question No: 4 ( Marks: 1 ) - Please choose one

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
Question No: 5 ( Marks: 1 ) - Please choose one

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

Question No: 6 ( Marks: 1 ) - Please choose one

Which of the following is not true about relational tables?
► Column values are of the same kind.


► Each row is unique.


► Each column must have a unique name.


►The sequence of rows is significant.



Question No: 7 ( Marks: 1 ) - Please choose one

In a conceptual model for a university, what type of relationship exists between Grade and Student entities?
► 1:1
► 1:M
► M:M
► Ternary

Question No: 8 ( Marks: 1 ) - Please choose one
 Controlling redundancy in a database management system DOES NOT help to
► avoid duplication


► avoid unnecessary wastage of storage space


► avoid unauthorized access to data


► avoid inconsistency among data




Question No: 9 ( Marks: 1 ) - Please choose one

Which of the following is INCORRECT with respect to file systems?


► At the physical level, pointer or hashed address scheme may be employed to provide a certain degree of data independence at the user level.
► A logical record is concerned with efficient storage of information in the secondary storage devices.
► Some physical organisations use pointers to record blocks to locate records on disk.
► The efficiency of a file system depends on how efficiently operations such as retrieve, insert, update, delete may be performed on the information stored in the file.



Question No: 10 ( Marks: 1 ) - Please choose one

Which of the following functions are NOT performed by a database administrator?


► Planning, designing and implementing database systems


► Establishing standards and procedures for database systems


► communicating with database users


► Allocation of storage locations and data structures



Question No: 11 ( Marks: 1 ) - Please choose one

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.


► 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.



Question No: 12 ( Marks: 1 ) - Please choose one

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.



Question No: 13 ( Marks: 1 ) - Please choose one

Which of the following is not a benefit of normalization?

► Minimize insertion anomolies
► Minimize deletion anomolies
► Minimize updation anomolies

► Maximize redundancy



Question No: 14 ( Marks: 1 ) - Please choose one
 Consider the following relation R and its sample data. (Consider that these are the only tuples for the given relation)


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.



Question No: 15 ( Marks: 1 ) - Please choose one

The Entity Relation Model models


► Entities, Relationships and Processes
► Entities and Relationships
► Relationships
► Entities

Question No: 16 ( Marks: 1 ) - Please choose one

As part of database naming conventions, attribute names should use suffixes such as ID, NUMBER or CODE for the _______.
► primary key
► foreign key
► index
► determinant



Question No: 17 ( Marks: 2 )

For which purpose do we use relational data model?

Question No: 18 ( Marks: 2 )

What major problem can occur if we do not normalize a relation into the first normal form?

Question No: 19 ( Marks: 2 )

In which situation do a recursive relationship exist?


Question No: 20 ( Marks: 3 )

What is DML (Data Manipulation Language)?

Question No: 21 ( Marks: 3 )

What are the three important objectives for using data types while specifying attributes?

Question No: 22 ( Marks: 5 )

Briefly explain super key in relation with primary key.

Question No: 23 ( Marks: 5 )

When is a functional dependency F said to be minimal?