Midterm

Question 1

python language

Answer 1

• Simple
• Intuitive and Open Source
• Scripting Language Interpreted
• Multi-platform
• Multi-paradigm

Question 3

interpreted language

Answer 3

• no cross-compiling
• computational costs
• multi platform

Question 4

module

Answer 4

• A module is a collection of functions that can be imported in other programs

Question 5

Strongly typed language

Answer 5

the language has strong constraints on the data type

Question 6

Dynamically typed language

Answer 6

the type can be changed

Question 7

Python interpreter

Answer 7

• An interpreted language at runt-time
• Code -> python code syntax checker translator -> (input ->) python execution environment (python virtual machine PVM) -> output
• Will work independently from the platform

Question 8

random function

Answer 8

• Generate pseudo-random numbers
• The seed allows the identification of a sequence (every time the function is called it returns the next random value)
• Two execution with the same seed will return the same sequence
• It is possible to generate real numbers, random.random() or integer numbers, random.randint(from,to) - (from,to) define the range)

Question 9

for loop example print 1 to 9

Answer 9

Question 10

information systems

Answer 10

• Collection, Storage, and processing of data
• Include a computer system for task automation
• A database management system (DBMS) is a software to support data management.

Question 11

data modeling

Answer 11

• The process of creating a data model for an information system
• Necessary to confer to data a structure useful in the context of a specific business process
• It can have several abstraction layers
• conceptual (drawing) -> logic (deatils of tables) -> physical (mySQL)

Question 12

Entity-Relationship model

Answer 12

• The Entity-Relationship model is an abstract model to represent the structure of data for a business process
• Typically used of relational databases
• Can represent concepts and relations among them

Question 13

entities

Answer 13

object categories with shared properties

Question 14

1.

relationships

Answer 14

connections among entities.

Question 15

many-to-many relationship

Answer 15

Question 16

one-to-many relationship

Answer 16

Question 17

one-to-one relationship

Answer 17

Question 18

attributes

Answer 18

• An entity always has a primary key (black bullet)
• Surrogate Key
• Composed Key
• Foreign Key

Question 19

Logic data Model

Answer 19

A logic data model allows the translation of a conceptual models into data structures

Question 20

SQL

Answer 20

• The Structure Query Language is the most used language for querying relational databases
• Three sub-languages:
  – DDL (Data Definition Language)
  – DML (Data Manipulation Language)
  – DCL (Data Control Language)

Question 21

Query Language: DDL

Answer 21

• Define metadata of structures and objects in a data base
• Useful in the design phase
• Create and manipulate a schema

Question 22

MySQL

Answer 22

• An open-source DBMS An open-source DBMS
• Community Edition is open-source
• Community Edition is open-source Community Edition in the Ubuntu Repository Community Edition in the Ubuntu Repository

Question 23

MySQL -Workbench

Answer 23

• The Workbench handles connection towards running MySQL Instances
• Once a connection is activated, it allows the management of the database
• Once a connection is activated, it allows the management of the database.

Question 24

MySQL -Schema

Answer 24

• A schema is a collection of tables
• In MySQL schema and database are synonyms

Question 25

Indexing

Answer 25

• An additional data structure designed to get fastest query response times
• Different type of indexing: BTREE, HASH

Question 26

Binary tree

Answer 26

A self-balancing tree data structure (generalization of binary search tree)

In a B-tree of order n: Every node has at most n children. Every internal node except the root has at least n/2 children. Every non-leaf node has at least 2 children. All leaves appear on the same level and carry no information. A non-leaf node with k children contains k−1 keys.

Question 27

Strcutured data

Answer 27

• prefiend schema

Question 28

Unstructured data

Answer 28

• Unstructured data have no referring schema and cannot be queried easily
• Examples: Text Files, Media data, Emails

Question 29

Semi-structured data

Answer 29

• Semi-structured data impose some form of structure Less constraints
• Tags can be used to define a partial structure– XML– JSON– CSV

Question 30

Pandas objects

Answer 30

Three main data structures:
* Series
* DataFrame
* Index

Question 31

Pandas Series

Answer 31

• Indexes can be customized
• Element are, then, accessible as in NumPy arrays
• Can be used as a dictionary mapping typed key to typed values
• Typing allows for high performance

Question 32

Pandas dataframe

Answer 32

• A DataFrame can be seen as an enhanced twodimensional array
• Both row indexes and column names are flexible
• A sequence of Series sharing the same indexes
• Can be created from loops, arrays
• Columns of a DataFrame can be accessed in different ways: As Individual Series, As a multi-dimensional array

Question 33

Access rows in indexed data

Answer 33

• Using custom indexes (the one defined by the data structure) –> loc
• Using native indexes (the implicit ones from underying arrays) –> iloc
• can also be used defining ranges [from:to]