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Field aggregation

As explained in Data-Oriented Programming: Reduce software complexity

Field aggregation is the transformation of values from a field across multiple records into one combined value.

Field aggregation turns repeated field values across related records into one combined value. A practical pipeline groups rows by an identifier, then collects each group’s field values into a list. section 10.4

Books and authors

Rows for “7 Habits of Highly Effective People” become one map with ISBN, title, and authorNames containing Sean Covey and Stephen Covey; a single-author book becomes a one-element list.

How Data-Oriented Programming: Reduce software complexity covers it

How deep it goes
Explains grouping, extraction, representative-row transformation, generalization, and testing, stopping short of database-side aggregation.
Examples
Uses book-and-author rows, ISBN grouping, authorNames lists, generalized helpers, and an equality-based test.
What it assumes
Assumes familiarity with lists of maps and query results while teaching the transformation step by step.
What you can do after
Apply field aggregation by grouping rows and parameterizing the source and destination field names.
How it connects
Connects SQL query results with grouping, database operations, and testing.
Cover of Data-Oriented Programming: Reduce software complexity
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Related concepts

This explainer was generated by Manning's knowledge graph from the text of Data-Oriented Programming: Reduce software complexity. The section links point to the parts of the book it draws on.