hierarchical-data

What is the most efficient/elegant way to parse a flat table into a tree?

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Now that MySQL 8.0 supports recursive queries, we can say that all popular SQL databases support recursive queries in standard syntax. WITH RECURSIVE MyTree AS ( SELECT * FROM MyTable WHERE ParentId IS NULL UNION ALL SELECT m.* FROM MyTABLE AS m JOIN MyTree AS t ON m.ParentId = t.Id ) SELECT * FROM MyTree; … Read more

What are the options for storing hierarchical data in a relational database?

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My favorite answer is as what the first sentence in this thread suggested. Use an Adjacency List to maintain the hierarchy and use Nested Sets to query the hierarchy. The problem up until now has been that the coversion method from an Adjacecy List to Nested Sets has been frightfully slow because most people use … Read more

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