Hi Maurizio, if you can manipulate your MySql db a simpler solution can be the following:
1 - Add a new field for your hierarchical data inside your table MY_HIERARCHICAL_FIELD 2 - Populate directly in MySql this new field with a simple procedure* 3 - Import the data in your Solr index *The MySql procedure could be similar to the following: 1 - iterate your table and find your top records not yet elaborated (it means with MY_HIERARCHICAL_FIELD empty and no father or with a father with MY_HIERARCHICAL_FIELD NOT empty) 2 - find the anchestor of the founded records 3 - Update your MY_HIERARCHICAL_FIELD field with the value of MY_HIERARCHICAL_FIELD father || '/' || MY_ID current At the end of the procedure you will have your MY_HIERARCHICAL_FIELD populated with values like '12/35/45/154' The value '12/35/45/154' means that the current record has id 154 and it is a child of record 45 that is a child of 35 that is a child of 12 that has no parents. 2012/10/2 Maurizio Cucchiara <mcucchi...@apache.org> > Hi all, > I'm trying to import some hierarchical data (stored in MySQL) on Solr, > using DataImportHandler. > Unfortunately, as most of you already knows, MySQL has no support for > recursive queries, so there is no way to get hierarchical data stored > as an adjacency list. > So I considered writing a DIH custom transformers which given a > specified sql (like select * from categories) and a value (f.e. > category_id): > * fetches all data > * builds an hierarchical representation of the fetched data > * optionally caches the hierarchical data structure > * then returns 2 multi-valued lists which contain the 2 full paths (as > String and as Number) > > Is there something out of the box? > Alternatively, does the above approach sound good? > > TIA > > > Twitter :http://www.twitter.com/m_cucchiara > G+ :https://plus.google.com/107903711540963855921 > Linkedin :http://www.linkedin.com/in/mauriziocucchiara > VisualizeMe: http://vizualize.me/maurizio.cucchiara?r=maurizio.cucchiara > > Maurizio Cucchiara >
