It seems this problem is quite popular on programming.
I have a table that among its fields have Id and ParentId.
The question is, how to, using Hibernate, handle properly a task like “retrieve all children of a given node”
Right now I got something like a recursive loop that finds children given a parentId, but at 10000 rows in the table is just insane.
All I can find is that people say this DB structure is not adequate for big amounts of data, but I’m already on that path. What can I do other than killing my DB with 10000 small queries?
When a hibernate object has a one-to-many property, each call to get the next child forces a query. This is called “lazy loading” and increases performance by grabbing them on demand. You can force hibernate to “eagerly load” the set all in one query by setting the lazy property on your mapping. More information is available in the documentation:
http://docs.jboss.org/hibernate/core/3.3/reference/en/html/performance.html#performance-fetching-lazyproperties