New Job 1

Question 1

What is the difference between Java and Javascript

Answer 1

Key differences between Java and JavaScript:

• Java is an OOP programming language while Java Script is an OOP scripting language.
• Java creates applications that run in a virtual machine or browser while JavaScript code is run on a browser only.
• Java code needs to be compiled while JavaScript code are all in text.

Question 2

package inputdemo
import java.util.Scanner

what is java.util.Scanner?

Answer 2

a class

Question 3

objects are created from templates known as…

Answer 3

classes

Question 4

Scanner input = new Scanner(System.in); - name each part

Answer 4

Scanner is the class
input is the name of the Scanner object we're creating

Question 5

In relational databases, rows are also called….

Answer 5

tuples or records

Question 6

In relational databased, columns are also called…

Answer 6

attributes

Question 7

In RDs, each row needs a…

Answer 7

unique key

Question 8

A foreign key is

Answer 8

A column for the unique key of the linked row, which is used to link rows in a table to a row in another table

Question 9

Primary key

Answer 9

Specific choice of a minimal set of attributes (columns) that uniquely specify a tuple (row) in a relation (table)

Question 10

Surrogate key

Answer 10

an attribute created to function as a key (ie. case_id). Usually the primary key

Question 11

Natural key

Answer 11

Real-world observations (like time and location of birth), usually the alternate keys

Question 12

Candidate key

Answer 12

Minimal superkey for that relation; that is, a set of attributes such that:

1. The relation does not have two distinct tuples (i.e. rows or records in common database language) with the same values for these attributes (which means that the set of attributes is a superkey)
2. There is no proper subset of these attributes for which (1) holds (which means that the set is minimal).

Question 13

Prime attributes

Answer 13

Attributes that are included in the candidate key

Question 14

Superkey

Answer 14

a set of attributes of a relation variable for which it holds that in all relations assigned to that variable, there are no two distinct tuples (rows) that have the same values for the attributes in this set. The set of all attributes is a trivial key (because no two rows can be exactly the same)

Question 15

When a PK migrates to another table, it becomes a….

Answer 15

foreign key

Question 16

Other models besides the relational model include…

Answer 16

the hierarchical database model and the network model

Question 17

A table is also knowns as a…

Answer 17

Relation or Base relvar

Question 18

A result set is also known as a…

Answer 18

View or Derived relvar

Question 19

Relations can be modified using the….

Answer 19

insert, delete, and update operators

Question 20

What does ACID stand for?

Answer 20

Atomicity, Consistency, Isolation, Durability

Question 21

What is ACID?

Answer 21

It’s a set of properties of database transactions intended to guarantee validity even in the event of errors, power failures, etc

Question 22

What is the Atomicity property?

Answer 22

It requires that each transaction be “all or nothing”: if one part of the transaction fails, then the entire transaction fails, and the database state is left unchanged

Question 23

What is the consistency property?

Answer 23

The consistency property ensures that any transaction will bring the database from one valid state to another

Question 24

What is they isolation property?

Answer 24

The isolation property ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were executed sequentially, i.e., one after the other.

Question 25

What is the durability property?

Answer 25

The durability property ensures that once a transaction has been committed, it will remain so, even in the event of power loss, crashes, or errors. In a relational database, for instance, once a group of SQL statements execute, the results need to be stored permanently (even if the database crashes immediately thereafter)

Question 26

What are base relations?

Answer 26

Relations that store data

Question 27

What are derived relations?

Answer 27

Relations that are computed by applying relational operations to other relations, they do not store data. They can be used as an abstraction layer

Question 28

What is an abstraction layer?

Answer 28

In computing, an abstraction layer or abstraction level is a way of hiding the implementation details of a particular set of functionality, allowing the separation of concerns to facilitate interoperability and platform independence

Question 29

What is an integer?

Answer 29

1, 2, -20, 0

Question 30

Natural number

Answer 30

0, 1, 2 (not negative)

Question 31

Real number

Answer 31

.01, 0., -.01, 5. In SQL, can’t be more precise than 64 values

Question 32

Float in SQL

Answer 32

Specify precision. So FLOAT(8) wouldn’t accept 9-number numbers

Question 33

What is a stored procedure?

Answer 33

is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database data dictionary.

Question 34

What are 2 examples of a stored procedure?

Answer 34

Data validations, access control mechanisms

Question 35

How are stored procedures invoked?

Answer 35

CALL or EXECUTE

Question 36

Cardinal vs. Ordinal

Answer 36

Cardinal tells you how much of something there are, ordinal tells you where the number is in the group. So For set {1, 3, 5, 7}, the cardinality of the set is 4, and the ordinality of 3 is 2.

Question 37

What is Pascal Casing?

Answer 37

ThisIsPascalCasing, it’s convention for naming classes

Question 38

What can the contents of a class include?

Answer 38

Fields, constructors, methods, interfaces, methods, and other classes