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In the database literature, the lore has been to first design a schema and then predict the query mix to decide on a tuning strategy. This approach can work, but it is risky and error prone. A small misjudgment of the query mix can lead to vastly inferior performance. For many applications a better strategy is to index every foreign key. That is often sufficient and further tuning is unnecessary.
Continue reading Please Index Foreign Keys
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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.
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Many organizations today outsource software development. You, the customer, specify your requirements and the vendor is supposed to build software that meets your requirements. But requirements are not sufficient as a specification. With this common scenario, you have no control over the quality of the software being built. Furthermore, you have no visibility into the software’s structure. You can improve this situation by adding a data model and a database design to your specifications.
Continue reading Do Not Outsource the Data Model and the DB Design
It’s been 25 years since these GE Research folks published “Object-Oriented Modeling and Design.” From left to right, Bill Lorensen, Jim Rumbaugh, Mike Blaha, Bill Premerlani and Fred Eddy. We had no idea at the time that the book would sell over 200,000 copies.