18 lines
926 B
Text
18 lines
926 B
Text
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DataMapper plugin allowing the creation of nested sets from data models.
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Provides all the same functionality as dm-is-tree, plus tons more! Read on.
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== What is a nested set?
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Nested set is a clever model for storing hierarchical data in a flat table.
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Instead of (only) storing the id of the parent on each node, a nested set puts
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all nodes in a clever structure (see Example below). That is what makes it
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possible to get the all of the descendants (not only immediate children),
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ancestors, or siblings, in one single query to the database.
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The only downside to nested sets (compared to trees] is that the queries it
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takes to know these things, and to move nodes around in the tree are rather
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complex. That is what this plugin takes care of (+ lots of other neat stuff)!
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Nested sets are a good choice for most kinds of ordered trees with more than
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two levels of nesting. Very good for menus, categories, and threaded posts.
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