Big Data Overview and Key Concepts

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Questions and Answers

Which type of analysis focuses on understanding changes in data over a period of time?

Descriptive analysis

Statistical analysis

Trend analysis (correct)

Comparative analysis

What is one of the primary functions of INE in relation to economic data?

To offer a range of statistical data on various aspects of the country (correct)

To provide historical data only

To facilitate international trade negotiations

To analyze genetic factors in demographics

Which of the following is NOT a type of analysis mentioned in the content?

Qualitative analysis (correct)

Trend analysis

Comparative analysis

Descriptive analysis

Which data source is indicated as offering interactive tools for data analysis?

INE Signup and view all the answers

What type of survey data does INE provide regarding the labor market?

Survey data to active population Signup and view all the answers

What should be done when data redundancies and inconsistencies begin to appear in a list?

Convert the list to a database managed by a DBMS Signup and view all the answers

Which of the following is NOT a function performed by a Database Management System (DBMS)?

Formatting text for user interfaces Signup and view all the answers

At which level of database design are the main entities and relationships defined in a technology-agnostic way?

Conceptual Design Signup and view all the answers

What does the integrity function of a DBMS ensure?

Accurate and consistent data through validation rules Signup and view all the answers

Which of the following tasks is involved in the manipulation aspect of a DBMS?

Inserting, updating, and deleting records Signup and view all the answers

What is the primary advantage of using indexing within a DBMS for performance optimization?

Increases the speed of data retrieval processes Signup and view all the answers

What characterizes the physical level of database design?

Describes the actual storage method of data Signup and view all the answers

Which of the following accurately describes the purpose of a primary key in a database?

It uniquely identifies each row in a table. Signup and view all the answers

What is the significance of using foreign keys in relational databases?

To connect two tables by referencing the primary key of another table. Signup and view all the answers

Which data type would you choose to store a file that contains an image in a database?

BLOB Signup and view all the answers

How does SQL facilitate data analysis for businesses?

By allowing the retrieval of insightful information through complex queries. Signup and view all the answers

When defining a DECIMAL data type as DECIMAL(5,2), what does each number represent?

5 total digits with 2 after the decimal point. Signup and view all the answers

What type of SQL command would you use to remove a record from a database table?

DELETE Signup and view all the answers

Which SQL command structure correctly creates a new table with two columns: 'Name' and 'Age'?

CREATE TABLE People (Name CHAR(30), Age INT); Signup and view all the answers

Which SQL data type would be most appropriate for storing a person's birthdate?

DATE Signup and view all the answers

What role does SQL play in the field of healthcare?

Essential for managing patient records and data efficiently. Signup and view all the answers

What is the purpose of using a subquery in the context of retrieving customer names?

To retrieve one or more values based on criteria Signup and view all the answers

Which of the following accurately describes a correlated subquery?

It uses information from the outer query to filter results. Signup and view all the answers

What is a key limitation of using Excel as a flat-file database?

It lacks complex relational structures and integrity constraints. Signup and view all the answers

In which situation would using Excel's Data Model be most beneficial?

When working with large datasets requiring complex relationships. Signup and view all the answers

How does the use of a subquery in the SELECT statement enhance its functionality?

By providing calculated fields based on other related data. Signup and view all the answers

What happens when a subquery in a WHERE clause compares a column to an aggregate value?

It filters the results based on the average of all records. Signup and view all the answers

Which SQL statement will result in retrieving information about cars rented by customers who rented more than once?

SELECT * FROM cars WHERE carid IN (SELECT carid FROM rentals GROUP BY customerid HAVING COUNT(*) > 1) Signup and view all the answers

What key advantage does Excel have as a tool for managing small datasets?

It enables quick analyses without needing extensive database knowledge. Signup and view all the answers

What SQL function would effectively retrieve the total amount spent by each customer?

SUM Signup and view all the answers

Study Notes

Big Data

Data is essential for decision-making in all areas of business
Global data volume in 2025 is estimated at 175 zettabytes (ZB) (1 ZB = 1 billion gigabytes)
Daily Internet user data generation is around 2,500,000 GB
90% of data was generated in the last two years.

Five Vs of Big Data

Velocity: batch, near real-time, real-time, streams
Variety: structured, unstructured, semi-structured
Volume: terabytes, records, transactions, tables, files
Veracity: trustworthiness, authenticity, origin, reputation, accountability
Value: statistical, events, correlations, hypothetical

Data Sources

Social media platforms like Facebook, Twitter, and Instagram
Internet of Things (IoT) devices
Sensors generating data
80% of global data is unstructured (text, images, video).

Data Storage

Less than 20% of global data is stored in relational databases.
Big Data Architectures are used to store, process and analyse large volumes of data.
Cloud storage and NoSQL databases are used.
Different technologies are needed to manage large volumes.

Data Analysis Types

Descriptive analysis: summarizing and describing a dataset (e.g., unemployment by age in Spain)
Trend analysis: how data changes over time
Comparative analysis: comparing data between groups or variables (e.g., comparing unemployment rates in different regions of Spain)

Economic and Financial Data Sources

INE (Spanish National Statistics Institute): provides data on economic, demographic and social aspects
Ministry of Economy, Trade and Enterprise: provides data on financial data and statistics such as macroeconomic data, public finances, labor market information
Other sources include data from a variety of sources such as Madrid Stock market, European statistics office, World bank and the International Monetary Fund

Introduction to Databases

Databases are used to manage, store, and retrieve information efficiently in the digital world
Different ways to store and manage information existed before databases (e.g., paper, magnetic tapes, books)
These methods lacked the ability to handle large volumes of data efficiently in a secure manner
Database management systems (DBMS) provide an interface between users and data and enable efficient data management
Database management systems provide tools for data creation, management, manipulation and retrieval

SQL and Its Importance

SQL (Structured Query Language): essential for managing and manipulating relational databases, used in most relational DBMS
It supports tasks like creating, reading, updating, and deleting data.
Useful for Data Analysis(extracting meaningful insights) and to handle large data volumes
Widely used in real-world applications such as finance, business intelligence, healthcare, and e-commerce.

Main Data Types in SQL

A table's columns have different data types.
Common data types include: INT, FLOAT, DOUBLE, DECIMAL, VARCHAR, CHAR, TEXT, DATE, TIME, DATETIME, TIMESTAMP, and BLOB.

SQL Queries

Creating tables, selecting records, inserting records, updating records, and deleting records are some of the SQL tasks
Joins are essential to combine data from multiple tables on related columns.
Subqueries are used in SQL to perform complex queries with queries nested inside another query.
Operators are used to perform arithmetic calculations, comparisons and logical evaluations.

Using Microsoft Excel as a Database

Excel can be used as a flat-file database, especially for storing and managing small datasets. It can be useful for smaller applications and quick analysis
Excel lacks some functions of a full database system (e.g. integrity constraints and scalability)
Excel's data model supports relationships between tables.
Limitation of Excel as relational database: not robust and does not enforce referential integrity

NoSQL Databases

NoSQL databases are used for non-tabular data, unlike relational database.
They are highly scalable and versatile, used for Big Data and real-time analysis.
Document stores store data as documents (e.g., JSON).
Graph databases model data as nodes and connections.
Key-value stores store data by key and value pairs.

Power BI as a Database Tool

Power BI can connect to various data sources (SQL databases, Excel, etc.) and provide visualization.
It is suitable for data exploration, analysis, and business intelligence, but does not store data centrally.
It allows users to generate reports, dashboards, and analyses, but unlike full database systems, it does not store data permanently.

Relational Databases

Tables are organized in rows and columns and connected using relationships (keys).
Relationships exist to link tables for complex queries and data integrity.
Normalization is essential for efficient database design and reduces redundancy.
Relational databases are structured and efficient for handling data with strong relationships.

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Description

Explore the fundamentals of Big Data, including its importance in decision-making and the staggering statistics surrounding global data generation. This quiz covers the Five Vs of Big Data, common data sources, and storage solutions used in the industry today.