Question

True False Select the most correct answer. Question 1 (1 point) Most databases are just in...

True False

Select the most correct answer.

Question 1 (1 point)

Most databases are just in 1NF.

Question 1 options:

True
False

Question 2 (1 point)

A subquery is always preferred over a join.

Question 2 options:

True
False

Question 3 (1 point)

A database may consist only of multiple files.

Question 3 options:

True
False

Question 4 (1 point)

A database may exist without a database management system.

Question 4 options:

True
False

Question 5 (1 point)

The insert statement may violate constraints.

Question 5 options:

True
False

Question 6 (1 point)

The relational model is a new model for databases.

Question 6 options:

True
False

Question 7 (1 point)

Databases management systems are generally compatible with one another.

Question 7 options:

True
False

Question 8 (1 point)

You must have an FK constraint to join one table to another.

Question 8 options:

True
False

Question 9 (1 point)

A relation is automatically in 2NF if it's primary key consists of one column that all the other columns functionally depend on.

Question 9 options:

True
False

Question 10 (1 point)

A left join may result in NULLs on the right hand side of the result.

Question 10 options:

True
False

Question 11 (1 point)

A plain text file will always be well organized enough to be used as a database.

Question 11 options:

True
False

Question 12 (1 point)

Typically an aggregate function will be used with the group by clause.

Question 12 options:

True
False

Question 13 (1 point)

SQLite supports the update statement on views.

Question 13 options:

True
False

Question 14 (1 point)

SQLite is often used as a replacement for custom file structures.

Question 14 options:

True
False

Question 15 (1 point)

A select statement must always return rows.

Question 15 options:

True
False

Multiple Choice

Select the most correct answer.

Question 16 (1 point)

If you wanted to get the amount of entries that exist, what would be the best aggregate function?

Question 16 options:

AVG

IF

COUNT

SUM

Question 17 (1 point)

Which of the following SQL statement(s) are not syntactically correct?

Question 17 options:

SELECT * FROM Order WHERE item = ‘Medium Pepperoni Pizza’;

SELECT artistId, count(*) FROM ArtistsAndAlbums WHERE artistname = ‘Red Hot Chili Peppers’ group by artistId;

none are correct

SELECT CodeName FROM SecretAgents WHERE Lastname = ‘Archer’;

all are correct

Question 18 (1 point)

DDL stands for:

Question 18 options:

Data Definition Language

Data Development List

Data Definition Layer

Data Derived Layer

Question 19 (1 point)

Which of the following would best describe a database?

Question 19 options:

a collection of unrelation key-value pairs

a data structure designed to be held in main memory for finding information

something boring about suppliers and parts

data mostly held on secondary storage, organized in a way allowing for relationships and fast retriveal

Question 20 (1 point)

Views are generally used for...

Question 20 options:

To replace tables entirely

Providing access to only certain information

Replacing RBAC Role-Based Access Control

All of the above

Question 21 (1 point)

Which of the following is correct?

Question 21 options:

SQLite is always the fastest database

Some databases, like MySQL, have many files in a DB

Low normal forms save the most space

High normal forms are always faster

Question 22 (1 point)

Databases, for the most part, are usually found generally following the rules of...

Question 22 options:

1NF

2NF

3NF

BCNF

Question 23 (1 point)

Which of the following is an object in the relational model?

Question 23 options:

attribute

relation

tuple

schema

all of the above

Question 24 (1 point)

In the relational model, a table is also called a/an...

Question 24 options:

Schema

Database

Entity

Relation

Question 25 (1 point)

Given a PK (Make, Model), select the option that represents a PK constraint violation:

Question 25 options:

(Honda, Accord), (Toyota, Camry) , (Toyota, 86), (Honda, Accord)

(Toyota, Camry), (Honda, Accord), (Mazda, 3), (Mazda, CX5)

(Honda, Accord), (Mazda, 3), (Mazda, 6), (Toyota, Camry)

(Toyota, Camry), (Honda, Accord), (Mazda, 3), (Mazda, 6)


Please answer with the correct answers above.

Homework Answers

Answer #1

Question 1

  • Generally the basic databases are in 1NF, since all databases may not always require normalization.

Therefore the correct option is “True”.

Question 2

  • A join combines records from two or more tables.
  • A subquery is a query within SQL query and subquery will be written within the WHERE clause.
  • The query using joins always is faster than an equivalent subquery.

Therefore the correct option is “False”.

Question 3

  • A database is a collection of data, it can have one or more files.

Therefore the correct option is “False”.

Question 4

  • A database is a collection of data stored on a computer or any hardware.
  • A Data Base Management System (DBMS) is a one type of software that helps to interact with databases. That is using DBMS we can create, edit and delete databases.
  • Data can be collected and stored systematically on a computer or on any hardware, without using DBMS.

Therefore the correct option is “True”.

Question 5

  • Constraints ensure the accuracy and reliability of the data , by specifying what type of data can be inserted into a table.
  • Constraint violation may occur when insertion, deletion, and update.

Therefore the correct option is “True”.

Question 6

  • Hierarchical model and network models are the old to databases.
  • Relational model and object oriented models are new to data bases

Therefore, the correct option is “True”.

Question 7

  • Databases management systems use their own data base model and their own representation of data.
  • Thus, generally, the database management systems are not compatible with one another.

Therefore the correct option is “False”.

Question 8

  • A join combines records from two or more tables based on the columns that are common.
  • Thus, even though there is no foreign key, join can be applied on two table if there is a common column.

Therefore the correct option is “False”.

Question 9

  • primary key consists of one column is called single-attribute primary key.
  • A relation automatically in at least 2NF, if it has single-attribute primary key and all other columns functionally depend that primary key.

Therefore the correct option is “True”.

Question 10

  • LEFT JOIN returns all records from the first table(left table) and the matched records from the second table(right table). If there is no match, the result will be NULL on the right hand side.

Therefore the correct option is “True”.

Question 11

  • Even though, data is organized will in a text file , it is not enough to be used as database, as the maintaining , accessing , modifying data takes to much time.
  • Also, data maintained in text file lacks integrity and may have redundancy.
  • Thus, a text file always, may not be a good choice as data base.

Therefore the correct option is “False”.

Question 12

  • Aggregate functions perform operations on the values of multiple rows and returns a single value.
  • The GROUP BY clause is frequently used with the aggregate functions to arrange the result in groups.

Therefore the correct option is “True”.

Question 13

  • SQLite does not support DELETE, INSERT or UPDATE statements on views, as SQLite views are read-only.

Therefore the correct option is “False”.

Question 14

  • Often, some applications use SQLite as the on-disk file format. That is, SQLite is used by those applications for internal data storage.

Therefore the correct option is “True”.

Question 15

  • suppose where clause is used with select statement and if the where condition is not matched any row, then select returns 0 rows.
  • Thus select may not always return rows.

Therefore the correct option is “False”.

Question 16

  • Aggregate functions are used to get summary
  • COUNT is used to find the number of entries that exist.

Thus, the correct option is “COUNT”

Question 17

  • There are no syntactical errors in all given SELECT statements.

Thus, the correct option is “all are correct”

Question 18

  • DDL is the abbreviation of Data definition language.

Thus, the correct option is “Data Definition Language”

Question 19

  • A database is a collection of data stored on a secondary storage of a computer or any hardware, for accessing information easily.

Thus, the correct option is “data mostly held on secondary storage, organized in a way allowing for relationships and fast retrieval”

Question 20

  • View is a subset of an original table and it is virtual. That is, view appears as a real table.
  • Views are used provide some level of security by hiding some rows or columns.

Thus, the correct option is “Providing access to only certain information”.

Question 21

  • Not only MySQL, but also other data bases may have many files in their DB.
  • Low normal forms may not save space as they have redundant data.
  • High normal forms may not always faster. They are faster if we use extra techniques like indexing.
  • SQLite is a simple software and thus it is faster.

Thus the correct option is “SQLite is always the fastest database”.

Question 22

  • Generally the basic databases are at least in 1NF. That is most of the data bases atleast follows rules of 1NF.

Thus, the correct option is “1NF”.

Question 23

  • A class represents a relation and an object represents a tuple.

Thus, the correct option is “Tuple

Question 24

  • Relational model database is a collection of relations, where each relation is nothing but a table.

Thus, the correct option is “Relation”.

Question 25

  • Primary key uniquely identifies each row. Insertion duplicate values leads to Primary key violation error.
  • In the given options, all tuples are unique, except in the first option. Duplicate exists for (Honda, accord) in the first option. It is a primary key violation.

Thus, the correct option is “(Honda, Accord), (Toyota, Camry) , (Toyota, 86), (Honda, Accord)”.

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