Database

Database mid 2020 exam

Drop table command cannot be used to drop a table referenced by a _______ which constraint?

How many tables will be generated after we do the mapping for the following shape?<img src="https://api.kasitteam.com/downloads/6363aa8c2b36bd1e3e986f8f/6mimna4758" width="725" height="688"/>

three tables: music and piano and guitar&nbsp;

four tables: music and piano and guitar and is a&nbsp;

two tables: piano and guitar&nbsp;

Choose the correct paragraph that describes the following ER diagram (or part of it):
<img src="https://api.kasitteam.com/downloads/6363aa8c2b36bd1e3e986f8f/513ib8z4f5" width="1024" height="399"/>

A company has employees. Each employee can be assigned to work on several projects. Every project has one employee only.

A company has many employees. Each employee can be assigned to work on one project which the company controls. One supervisor supervises several employees in the company&nbsp;

A company has employees. Each employee can be assigned to work on several projects which the company control. One supervisor supervises several employees in the company&nbsp;

A company has several employees. Each employee can be assigned to work on several projects which the company controls. Two supervisors monitor several employees in the company&nbsp;

Consider the following ERD and indicate how many attributes the ‘House’ relation will have?<img src="https://api.kasitteam.com/downloads/6363aa8c2b36bd1e3e986f8f/a9oe56w1l0" width="1024" height="517"/>

An attribute of a relation can also be a property of a relationship set

Choose the correct DDL statement to delete a column in a table:

<code>ALTER TABLE table_name DROP COLUMN column_name;</code>

<code>DROP COLUMN table_name column_name;</code>

<code>ALTER TABLE table_name DELETE COLUMN column_name;</code>

<code>DELETE COLUMN table_name DROP column_name;&nbsp;</code>

All the following are attribute types, EXCEPT:

The Primary key of a Weak Entity Set is:

The combination of the Primary key of the Weak Entity Set with the Primary key of the Strong Entity&nbsp;

The combination of the discriminator with the Primary key of the Strong Entity&nbsp;

The combination of the Super Key of the Weak Entity Set with the Primary key of the Strong Entity&nbsp;

The combination of the Foreign Key of the Weak Entity Set with the Primary key of the Strong Entity&nbsp;

In which Normal Form the following relation are:
<img src="https://api.kasitteam.com/downloads/6363aa8c2b36bd1e3e986f8f/h2v2sh8qzf" width="1024" height="1010"/>

Elimination of partial functional dependency is a necessary step for the database to be in SECOND NF.

What is the result of the following TWO DDL statements: 

<code>Create table Employee(EID varchar(5), Ename varchar(25), primary key(EID));</code>
 
<code>Create table Department (DID varchar(5), Dname varchar(25), EID varchar(5), primary key(DID), Foreign key(EID) references Employee(EID));</code>

Two tables will be created with a one-to-many relationship, the Employee table is the many side.

Two tables will be created with no relationship.

One table will be created with unary one-to-many relationship&nbsp;

Two tables will be created with one-to-many relationship, the Department table is the many side.

Based on the emp schema structure below, which of the following commands will decrease the size of the Dep_ID column from 5 to 4?

<code>ALTER TABLE emp MODIFY Dep_ID (4);</code>

<code>ALTER TABLE emp MODIFY Dep_ID CHAR(4);</code>

<code>ALTER TABLE emp MODIFY Dep_ID CHAR(5-1);</code>

<code>ALTER TABLE emp MODIFY Dep_ID (5)-1;&nbsp;</code>

Select the correct table(s) mapping that will be generated from the following ERD: 
<img src="https://api.kasitteam.com/downloads/6363aa8c2b36bd1e3e986f8f/6fundkascn" width="1024" height="310"/>

Music (MID, date) and piano (PID)

Music (MID) and Piano (PID, date)&nbsp;

Music (MID, date, PID) and piano (PID)&nbsp;

In a relationship when primary key from one entity is also defined as a field in a second entity this field in the second entity is referred as _______.
&nbsp;

Based on the emp schema structure below, which of the following commands will increase the size of the ID column from 5 to 6? 

<code>emp(Name varchar(20), ID char(5), Dep_ID char(5), Salary numeric(8.2));</code>

<code>ALTER TABLE emp MODIFY ID(6);</code>

<code>ALTER TABLE emp MODIFY ID CHAR(5)+1;</code>

<code>ALTER TABLE emp MODIFY ID CHAR(6);</code>

<code>ALTER TABLE emp MODIFY ID(5 + 1);</code>

In a relational database, we use _______ when there is a situation where some entities in a table do not participate in any relationship in the relationship set
&nbsp;

Relationship between or among entities&nbsp;

Relationship between or among relations&nbsp;

a Links between or among relationships&nbsp;

Relationship between or among attributes&nbsp;

All the following statements about weak and strong entity sets are True, Except:

The PK of the weak entity set is only formed by the primary key of the strong entity set&nbsp;

In ER-Diagram, the identifying relationship of a weak entity is represented as a double diamond&nbsp;

An entity set that does not have a primary key is referred to as a weak entity set&nbsp;

PK of the strong entity set is not explicitly stored with the weak entity set&nbsp;

The weak entity set depends on the existence of the strong entity set&nbsp;

TRUE large source set is generated, suitable for a responsive image. If the <code>sizes</code> property includes sizes such as <code>50vw</code>, which represent a percentage of the viewport width, then the source set is trimmed to not include any values which are too small to ever be necessary.&nbsp;