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Unstructured data

As explained in AI-Powered Search

Unstructured data is information without a rigid predefined schema, often containing rich content and relationships in flexible forms such as text, images, video, and audio.

A search engine may index text, images, audio, and video that do not fit a predefined database schema. Calling this information “unstructured” is useful shorthand, but it can be misleading. Sentences have grammar and punctuation; images arrange colors into pictures; audio can carry words, music, and tone. The challenge is not an absence of structure, but extracting meaning from flexible forms. section 2.1 section 2.1.1

A SQL join links rows through an explicit shared value, such as a company ID. Search documents can also contain shared values, but their relationships are usually embedded in their content rather than declared as keys. A repeated event name, for example, can connect two separately indexed documents. Different phrases may also refer to the same entity, allowing a less exact connection through entity resolution. section 2.1.2 section 2.1.3

Finding a connection across documents

Suppose one search document says someone will speak at a conference and another describes that conference. Their shared conference name acts much like a join value. If two documents instead use a full name and a first name for the same person, connecting them requires resolving those different phrases to the same entity. A matching name alone can also be ambiguous: different people may share its spelling. section 2.1.3

Figure 2.5 Fuzzy foreign keys. In this example, the same entity is being referenced using different terms, and a join is occurring based upon multiple phrases resolving to the same entity.
figure

The diagram shows a fuzzy connection: separate phrases refer to the same entity, so an exact shared term is not required. section 2.1.3

Event logs show how the categories can overlap: a structured date and event type may accompany a free-text message, making the record semi-structured. Across a search collection, connections among terms, entities, and documents can form a rich graph of domain knowledge. Those connections help search move beyond exact keyword occurrence, but ambiguous language makes context important. section 2.1.1 section 2.1.3 section 2.7

How AI-Powered Search covers it

How deep it goes
Defines the term, compares document links with SQL joins, and works through entity resolution; defers hands-on implementation.
Examples
Uses text, media, event logs, conference documents, and differently written person names to expose structure and ambiguity.
What it assumes
Introduces SQL rows and foreign keys as a comparison before explaining document relationships.
What you can do after
Evaluate/understand how search documents can be related without explicit foreign keys and why ambiguous matches need care.
How it connects
Connects unstructured data to SQL joins, entity resolution, knowledge graphs, and distributional semantics.

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Related concepts

This explainer was generated by Manning's knowledge graph from the text of AI-Powered Search. The section links point to the parts of the book it draws on.