1. Structured Data 

•  Everything is organized into fixed fields (like a spreadsheet).
• Easy for computers to read and search.
• Stored usually in relational databases (SQL).

Examples:
• Bank transactions (Date, Amount, Payee)
• Student grades (Name, Subject, Score)

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2. Unstructured Data

• No fixed format or organization.
• Hard for machines to search directly — needs special tools (like NLP or Computer Vision).
• Makes up ~80% of all data in the world!

Examples:
• A video recording (no obvious fields)
• A random tweet or Instagram post
• An image from a security camera

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3. Semi-Structured Data

• Partly organized — has some tags, keys, or structure, but not as rigid as a table.
• Flexible format — easier to manage than unstructured data, but not fully structured.

Examples:
• JSON from an API, XML documents

Structured, Unstructured, and Semi-structured Data

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Discrete v/s Continuous Data

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Measurement Scales for Data

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