Category Archives: UML

Six Data Modeling Patterns for Trees

StarAnise

picture by Thor via Flickr

Here’s a chapter from my book Patterns of Data Modeling. This chapter presents six data modeling patterns for trees — UML data models, IE data models, SQL queries, and examples. The book has much more information about patterns including patterns for directed graphs, patterns for undirected graphs, antipatterns, and archetypes.

DataModelingPatternsForTrees

Use Cases Are Overblown

randomSquarespicture by Jessica Fenlon via Flickr

A use case is a piece of functionality that an app can perform. Each app has many use cases and the use cases taken collectively specify the app’s functionality. For an example, consider an app for tracking library loan records. Some use cases are: borrow books, borrow magazines, return books, return magazines, renew books, renew magazines, pay fines, get library card, and change address.

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