> For the complete documentation index, see [llms.txt](https://vikram-bajaj.gitbook.io/cs-gy-6313-information-visualization/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vikram-bajaj.gitbook.io/cs-gy-6313-information-visualization/main-5/data-abstraction-and-transformation/types-of-datasets.md).

# Types of Datasets

A dataset (or data in general) can be viewed as a collection of items and attributes describing those items.

We have two broad categories of datasets:

1. Tables
2. Networks & Trees

## Tables

It is a collection of **rows** and **columns**, each row representing an item and each column an attribute.

Ideally, every item should have values for all attributes i.e. no missing values. Also, all items have the same *type* of value for a given attribute.

## Networks & Trees

They are used to represent **linked** items.

The items are represented as **nodes** and they are connected using **links**.

In trees, each node has only one parent.

Both nodes and links can have attributes.