2010/10/28 Luca7993 <[email protected]>: > Hi, > I have three small questions on nhibernate using: > > -it's possible to make the refresh of more entities in one single > round trip to database? > > -I have lazy load activated and also the second cache: > If I load a list of 150 entities (A), that have a many-to-one > relationship with another entities (B) (that are only few elements of > B...about 20), if entities B are not already in cache, there will be > "select n+1" query when I use A.B with lazy. > Is a good practice loading the B entities with a GetAll, before load > the list of A entities?
Google for batch-size that you can apply in your mappings. NHibernate can be configured to load multiple "expected needed" B instances when the first one is accessed. For this particular usecase, with only a small number of B, I guess GetAll() could also work. > > -if I need to load a list of 200 entities (A) that have a one-to-one > relationship with another Entities B, but in this case I need only one > properties of B (for example description), what should I need do? > can I "tell" to nhibernate to load only the property description of B > entity? Would it solve an actual problem if you could? You can use projections to load only specific data from the DB, but then it would no longer be your entities - it would just be a view of you data. Can be useful in reporting scenarios. /Oskar -- You received this message because you are subscribed to the Google Groups "nhusers" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nhusers?hl=en.
