The raw data entering your pipeline may come in a variety of formats.
We often distinguish between structured and unstructured data.
A typical form of structured data is a record from a relational database.
It follows a predictable format that can be easily processed. Unstructured data,
on the other hand, comes in files and doesn’t follow a predefined schema.
Examples include video files and text documents.
There’s also semi-structured data, which comes in internally structured file
formats like CSV, JSON, or XML, and which nonetheless requires some processing
to fit a relational-database format. Depending on your pipeline design, you
might transform the incoming data to fit predefined schemas.