CS403- Database Management Systems MidTerm Paper

MIDTERM  EXAMINATION

Spring 2010

CS403- Database Management Systems (Session - 2)

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ExamDate:	5/29/2010 12:00:00 AM

    

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 unauthorised 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?