Big Data Overview
30 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of analysis focuses on understanding how data changes over a specific period?

  • Trend analysis (correct)
  • Comparative analysis
  • Descriptive analysis
  • Predictive analysis

    • Which of the following is NOT a focus area of statistical data provided by the INE?

  • Demography and population
  • Labor market
  • Economy
  • Weather patterns (correct)

    • What aspect does comparative analysis study in the context of statistical data?

  • Insights on future trends
  • Forecasting economic conditions
  • Summarizing overall dataset characteristics
  • Differences and similarities between datasets (correct)

    • Which organization provides a comprehensive range of financial data and statistics?

    <p>Ministry of Economy, Trade and Enterprise</p> Signup and view all the answers

    What type of data is typically included in the demographic and population statistics offered by INE?

    <p>Census data, births, and deaths</p> Signup and view all the answers

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

    <p>To uniquely identify each record within a table.</p> Signup and view all the answers

    What SQL command would you use to remove all records from a table without deleting the table itself?

    <p>TRUNCATE TABLE TableName;</p> Signup and view all the answers

    Which SQL data type is most appropriate for storing a precise financial amount like 123.45?

    <p>DECIMAL(5,2)</p> Signup and view all the answers

    In SQL, what does NOT NULL signify when defining a table column?

    <p>The column cannot hold a null value.</p> Signup and view all the answers

    What is the primary benefit of using foreign keys in a relational database?

    <p>To enforce data integrity and avoid data duplication.</p> Signup and view all the answers

    When is the TIMESTAMP data type particularly useful in a database application?

    <p>When automatic updates of date and time are required.</p> Signup and view all the answers

    Which of the following represents a common application of SQL in the healthcare sector?

    <p>Storing and retrieving electronic medical records.</p> Signup and view all the answers

    What is the purpose of the LIKE operator in SQL?

    <p>To find records matching a specified pattern in string fields.</p> Signup and view all the answers

    Which SQL function would you use to find the number of characters in a car model?

    <p>LENGTH</p> Signup and view all the answers

    How would you modify a query to exclude records where the return date is null?

    <p>SELECT * FROM rentals WHERE NOT (returndate IS NULL);</p> Signup and view all the answers

    Which SQL syntax correctly demonstrates using a subquery?

    <p>SELECT * FROM cars WHERE carid IN (SELECT carid FROM rentals);</p> Signup and view all the answers

    Which of the following SQL commands correctly concatenates a customer's name and phone number?

    <p>SELECT CONCAT(CustomerName, ' ', CustomerPhone) AS FullContact FROM Customers;</p> Signup and view all the answers

    What is the effect of using the TRIM function in SQL?

    <p>To remove leading and trailing spaces from a string.</p> Signup and view all the answers

    Which statement about the RIGHT function is correct?

    <p>It extracts characters from the end of the string.</p> Signup and view all the answers

    In which clause can subqueries be effectively utilized?

    <p>Both WHERE and HAVING clauses.</p> Signup and view all the answers

    Which SQL command would you use to replace occurrences of 'S' with 's' in a customer name?

    <p>SELECT REPLACE(customer_name, 'S', 's') AS name FROM customer;</p> Signup and view all the answers

    Which SQL statement correctly retrieves the customer who has rented the most expensive car?

    <p>SELECT CustomerName FROM customers WHERE customerid = (SELECT customerid FROM rentals ORDER BY totalcost DESC LIMIT 1);</p> Signup and view all the answers

    What is the purpose of the correlated subquery in the provided SQL example?

    <p>To find employees whose salaries exceed the average salary of their respective departments.</p> Signup and view all the answers

    Which feature of Excel allows users to create relationships and analyze data from multiple tables?

    <p>Excel Data Model</p> Signup and view all the answers

    Why might one prefer using Excel as a database for small projects?

    <p>It allows for rapid prototyping and data exploration.</p> Signup and view all the answers

    When would you use a subquery in the SELECT clause?

    <p>To summarize total spending by customers as part of the output.</p> Signup and view all the answers

    What limitation does Excel have compared to a relational database management system (RDBMS)?

    <p>It lacks the ability to establish relationships between tables.</p> Signup and view all the answers

    Which query would correctly retrieve details of cars rented by customers who have rented more than twice?

    <p>SELECT * FROM cars WHERE carid IN (SELECT carid FROM rentals WHERE customerid IN (SELECT customerid FROM rentals GROUP BY customerid HAVING COUNT(*) &gt; 2));</p> Signup and view all the answers

    What is the primary characteristic of a flat-file database like Excel?

    <p>It operates through a single table or worksheet without relational capabilities.</p> Signup and view all the answers

    In the context of querying with subqueries, what does using the IN clause accomplish?

    <p>It limits the output to results matching certain values from another query.</p> Signup and view all the answers

    Study Notes

    Big Data

    • Data is crucial for decision-making in all business areas
    • Global data volume is projected to reach 175 zettabytes (ZB) in 2025, up from 2 ZB in 2010
    • Daily internet data generation is around 2,500,000 gigabytes
    • 90% of data generated in the last two years
    • 5 V's 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)
      • Value (statistical, events, correlations, hypothetical)

    Data Sources

    • Main sources include Facebook, Twitter, Instagram, and Internet of Things (IoT) devices
    • Twitter averages 500,000 tweets per minute
    • Instagram has 347,222 posts per minute
    • IoT involves 75 million connected devices generating data

    Data Storage

    • Less than 20% of global data stored in relational databases
    • 80% of global data unstructured (text, images, video)
    • Big Data is stored in big data architectures, cloud, and NoSQL databases
    • Different technologies needed for storing, processing, and analyzing large data volumes

    Storage Types

    • HDFS (Hadoop Distributed File System): used for storing large, distributed data where high redundancy (copies of data) required
    • Data Lake: A centralized repository for storing raw data for long-term analysis
    • NoSQL: flexible, fast and suitable for unstructured data
    • Relational (SQL): High consistency, suitable for well-structured data needing integrity

    Economic and Financial Data Sources

    • Several data sources available for economic and financial analysis
    • Data includes unemployment, demographic, and social statistics
    • Data sources encompass various categories including demography, economy, labor market, companies, society, and financial statistics
    • Data used across various fields such as government, stock markets, banking, and EU statistics
    • Government bodies and organizations provide data.

    Introduction to Databases

    • Databases needed for managing data efficiently across industries
    • Several types of databases exist; including E-commerce Platforms, Social Media Networks, Banking and Financial Services, Healthcare systems
    • Databases were initially limited in searching, retrieval and storage capability of large amounts of data
    • Database management systems are used to store and manage information, like paper, magnetic tapes, and electronic files.

    SQL and its Importance

    • SQL (Structured Query Language) is used to manage and manipulate relational databases
    • Key actions performed with SQL include creating, reading, updating, and deleting data.
    • SQL enables performance, data analysis and extracting meaningful insights from data.

    Main Data Types

    • Data types in SQL include integer, float/double, variable-length and fixed-length text, date, time and timestamp
    • SQL data types are essential for organizing and storing information within a database.

    Main Structures

    • Creating tables: involves defining data types (columns) and actual data (rows)
    • Selecting Records: retrieves data from tables using queries; can use JOINs to link data from different tables
    • Inserting Records: inserts new data into tables
    • Updating Records: changes existing data in tables using WHERE clauses to target specific data
    • Deleting Records: removes entries from tables; needs WHERE clauses for targeting

    Database Design and Joines

    • Database design involves defining the structure, storage, and retrieval mechanisms of data in a database system
    • Joins (INNER, LEFT OUTER, RIGHT OUTER) combine rows based on related columns.

    Subqueries

    • Subqueries are queries embedded within SQL queries for complex analysis, with conditions and selection for specific results

    Using Excel as DB

    • Excel used as a a flat-file database for simple datasets and quick analysis
    • Data can be structured using tables, rows and columns

    NoSQL

    • Non-relational databases (NoSQL) are meant for storing, retrieving, and maintaining non-tabular data
    • Useful for handling large data volumes, flexible data formats, and rapid iterations
    • Several types of noSQL databases cater to different data needs
      • Document stores (e.g., MongoDB), Key-value stores (e.g., Redis), and Graph databases (e.g., Neo4j).

    Power BI

    • Power BI used for data analysis and visualization, not primary storage
    • Can connect to various data sources as a way to explore and analyze relational data
    • A powerful tool for creating custom data applications.

    Relational Databases

    • Relational databases store data in tables with columns and rows.
    • Relationships link tables to prevent data loss and redundancy.
    • Relationships are established using keys (primary and foreign).

    Normalization

    • Normalization is used to eliminate data redundancy and ensure data consistency
    • Multiple Normal Forms (1NF, 2NF, 3NF) are used for structuring and organizing data.

    Other Topics

    • Various Data types, validation, use of functions etc.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Big Data Concepts PDF

    Description

    Explore the essential concepts of Big Data, including its importance in decision-making across various business sectors. Delve into the 5 V's of Big Data, data sources, and storage solutions. Understand how data generation has evolved and the role of platforms like Facebook and Twitter in shaping this landscape.

    More Like This

    Big Data and Programming Paradigms Quiz
    18 questions

    Big Data and Programming Paradigms Quiz

    EarnestGreenTourmaline7771 avatar
    EarnestGreenTourmaline7771
    Big Data Sources
    30 questions

    Big Data Sources

    RicherNobelium avatar
    RicherNobelium
    Big Data Overview
    8 questions

    Big Data Overview

    WiseZeal avatar
    WiseZeal
    Big Data Overview
    30 questions

    Big Data Overview

    WiseZeal avatar
    WiseZeal
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser