DBI202 1400 Questions and Answers 2024

DBI202 1400 Questions and Answers 2024

In relational data model, an attribute is a column ** Answ** False

A data model is a notation for describing data or information. And the description
generally consist of: ** Answ** 3 parts *

DBMS stands for what? ** Answ** Database Management System *

Look at this line: MOVIES (Id, Name, Description) What the above represent? **
Answ** A schema

Look at the following data for table R: .............. ** Answ** R is a relation

Choose all correct statements: ** Answ** set of rows ,,Data Mode

Choose 3 important data models that we will study in database course ** Answ**
Network ,Hierachical,Relational

In relational data model, a tuple is a record or a row ** Answ** true

When the Relational Data Model first proposed? ** Answ** 1970

What is the oldest data model? ** Answ** Network Data Model

How many data models mentioned in our database course? ** Answ** 6

XML files are semi-structured data ** Answ** true

A relation is a list of tuples ** Answ** false

A relation is a set of tuples ** Answ** true

What is the father of relational data model? ** Answ** Adgar Codd

In relational data model, an attribute is a column ** Answ** false

A data model is a notation for describing data or information. And the description
generally consist of: ** Answ** 3 parts

A weak entity: ** Answ** both (a) and (b)

Give the relation R(XYZT) with the following FD's: XY -> Z ; XYT -> Z ; XYZ -> T ; XZ ->
T ** Answ** R is not in BCNF

,Given the relation schema R(XYZT) and functional dependencies F = {X->Z, T->Y}. **
Answ** both X->Z and T->Y

The highest normal form for relation schema R(XYZ) with functional dependencies: F =
{XY-> Z; Y->X; Z->Y } is: ** Answ** 3NF

Give the relation R(EFGH) with the following FD's: E -> F ; F -> E ; E -> H ; H -> F **
Answ** R is in 3NF

Give the relation R(ABCDE) with the following FD's: D -> C, CE-> A, D ->A, and AE ->D
** Answ** ABE

Which of the following relations is in Third normal form (3NF)? ** Answ** ACD -> B ;
AC -> D ; D -> C ; AC -> B

Let R(ABCDEFGH) satisfies the following functional dependencies: A -> B, CH -> A, B -
> E, BD -> C, EG -> H, DE -> F. ** Answ** ADG -> CH

Which of the following statements are correct? (choose 2) ** Answ** bo? in 3NF are
also in BCNF

Which of the following relations is in Boyce-Codd Normal Form (BCNF)? ** Answ**
BD -> C ; AB -> D ; AC -> B ; BD -> A

How many design principles are there in our course when drawing an ERD? ** Answ**
5

Which of the following are guidelines for designing the relational schema ? ** Answ**
All of the above

Choose the correct statements: When draw an ERD (choose 2): ** Answ**
We ,,when an entity

Given relation scheme R = (XYZTV) and functional dependencies:{XY -> ZTV and X ->
V}. So, we can say that: ** Answ** XY is a key for R

Consider a relation R(A,B,C,D,E) with functional dependencies: AB->C, B->D, and C-
>E. ** Answ** AB

The ER model means that: ** Answ** be close to a users perception of the data

Consider the following statement: "When drawing ERD, you should avoid saying
something in many different ways' ** Answ** Avoid Redundancy Principle

,Consider the following statement: "Entity Sets and their attributes should reflect the
reality" That above statement describes which principle? ** Answ** Faithfulness
principle

Choose the correct statements: When draw an ERD (choose 3): ** Answ** bo?
Redundancy is not important, so we can ignore it

Given the relation schema R(MNPQ) with FDs:{MN->P; MN->Q; PQ->M; PQ->N}. **
Answ** 3NF

The functional dependency A -> B for relation schema R(A,B.C,D) implies that **
Answ** value for A must have the same value for B

How many primitive relational algebra operators are there in our course? ** Answ**
6

Suppose relation R(A.B) has the tuples: ** Answ** None of the above

Suppose relation R(A.B) has the tuples: ** Answ** (3.4.6.8),(12.4.6)

Consider the following statement "When drawing ERD. you should avoid introducing
more elements into your design than necessary" ** Answ** Simplicity Count
Principle

Suppose relation R(A.B) has the tuples: ** Answ** (1.2.4.6.8),(1.2.2.4.6)

Suppose relation R(A.B) has the tuples: ** Answ** (5.6),(7.8)

Consider the following statement "When drawing ERD. if an entity has no non-key
attribute and it is the "one" in many-one relationship, then we should set r! to the
attribute of other entities" ** Answ** Picking the right kind of element principle

Consider the following statement "When drawing ERD. you should avoid drawing
entities that can not be uniquely identified by their own attributes" ** Answ** Avoid
Redundancy Principle

The LEN function in SQL Server is: ** Answ** A scalar function

What is the meaning of the LEN function in SQL Server? ** Answ** number of
characters of a string

How to remove all trailing blanks? ** Answ** We can use the RTRIM function

The following is the syntax for the DATEDIFF function: DATEDIFF ( datepart, startdate ,
enddate ) ** Answ** true

, How to remove all leading blanks? ** Answ** We can use the LTRIM function

What is the meaning of the ISNULL function? ** Answ** NULL with the BLANK
value

Which of the following is in-correct? ** Answ** SELECT datepart( �1-jan-09 �, day)

Which of the following is in-correct? ** Answ** SELECT datepart('1-jan-09', year)

Which of the following is in-correct? ** Answ** SELECT datepart( �1-jan-09', month)

How to convert a number to a string? (choose all possible) ** Answ**
CONVERT,,CAST

What is the meaning of the DATEADD function? ** Answ** adds an interval to a
date you specify

The CASE function is used to Evaluates a list of conditions and returns one of multiple
possible result expressions ** Answ** true

In SQL Server, an index is an on-disk structure associated with a table or view that
speeds up retrieval of rows from the table or view ** Answ** true

Clustered index is not a good choice for the columns that undergo frequent changes
** Answ** true

A table or view must have a clustered indexe and some non-clustered indexes **
Answ** false

SQL Server typically selects the most efficient method when executing queries.
However, if no indexes are available. SQL Server must use a full table scan ** Answ**
true

How many clustered index we can create in a table? ** Answ** 1

Indexes can be helpful for a variety of queries that contain SELECT, UPDATE, or
DELETE statements ** Answ** true

In SQL Server, indexes are automatically created when PRIMARY KEY and UNIQUE
constraints are defined on table columns ** Answ** true

In reality, an incorrect index choice can cause less than optimal performance **
Answ** true

You should define the clustered index key with as few columns as possible ** Answ**
true