1. What is Data? Data is any collection of facts, values, or measurements that can be recorded, stored, and processed by computers or humans.
Simple examples: Numbers (42), words (“hello”), dates (2025-08-06), true/false (yes/no), files, images, videos, etc.In technology: Data is the raw material for software, analytics, machine learning, business intelligence, etc.
2. Types of Data Data can be classified in several ways. The most common are:
A. By Structure Type Description Example Structured Organized in fixed fields/columns, like a table Databases, Excel spreadsheets Semi-Structured Has some organization but not a strict schema JSON, XML, CSV, log files Unstructured No pre-defined format or schema Images, videos, emails, PDFs
B. By Nature/Content Type Description Example Numeric Numbers, integers, decimals 100, 3.14, -7 Textual Words, sentences, text blocks “Customer name”, “Review: great product” Categorical Labels or categories Red/Green/Blue, Male/Female Boolean True/False, Yes/No, 0/1 true, false, 1, 0 Date/Time Dates, timestamps 2025-08-06, 12:30 PM Spatial Locations, coordinates GPS points, maps Multimedia Images, audio, video, graphics profile_pic.jpg, song.mp3, video.mp4
C. By How It Arrives Type Description Example Batch Collected and processed in chunks Daily sales report, nightly backups Streaming Arrives and processed in real-time Website clicks, sensor data, live chat
3. Sources of Data Data can come from almost anywhere. Here are typical sources in tech and business:
Source Description Example Transactional Systems that record daily business Sales databases, banking systems Operational Logs/events from running systems Web server logs, app logs, error logs External APIs Data from third-party services Weather APIs, social media APIs, payment APIs Manual Entry Human input Online forms, surveys, spreadsheets IoT/Sensors Physical devices measuring things Thermometers, cameras, GPS trackers Files/Blobs Uploaded or shared files CSVs, Excel, PDFs, videos Web Scraping Data extracted from websites Product prices, news headlines Public Data Sets Open government or community data Census data, COVID-19 stats, Wikipedia dumps Streaming Services Live feeds, events Kafka, Kinesis, Event Hubs
Summary Table Type Examples Structured SQL databases, Excel tables Semi-Structured JSON, XML, CSV Unstructured Images, emails, audio, PDFs Numeric 1, 2.5, -99 Textual “Hello”, “Feedback” Categorical “Red”, “Male”, “Success” Boolean true/false, 0/1 Date/Time 2024-05-23, 17:45 Batch Daily ETL jobs Streaming Real-time clickstream, IoT Sources Databases, APIs, Logs, Sensors, Files, Scraping
