hi kristen,
ojb does the join automatically:
query.create("select authors ...Autor where books.title like ?");this sample need a relationship-definition named 'books' and an attribute 'title' in class Books. the relationship 'books' is a bidirectional m:n relationship based on the table writtenBy.
jakob
kristen schrieb:
Hello !
First, sorry for my english...
I would like to create a request which are based on a m:n relationships.
For example :
a book can be written by several authors and several authors can write books.
This is the relation :
book <-> writtenBy <-> author
For example, How can I obtain the name of all the author who have written the book "my book" ?
I have the following code but I don't know how can I put several classes after the "from" :
Transaction tx = odmg.newTransaction(); tx.begin(); OQLQuery query = odmg.newOQLQuery(); String queryStr = "select auhors from " + Author.class.getName()+ .... ?
query.create(queryStr); GroupsList = (List) query.execute(); tx.commit();
Thank you for your help
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