A row in the DB is the representation of the state of one object: which one?
-- Fabio Maulo El 22/10/2010, a las 12:05, Brian Chavez <[email protected]> escribió: Hi Fabio, Row 5 can be A, B, and C, depending on which one I'm requesting. The class hierarchy at A implements Id. class A{ int Id{get;set;} AProperty{get;set;} //Mapped to ColumnA in Table 1 } class B : A { BProperty{get;set;} //Mapped to ColumnB in Table 1 } class C : B { CProperty{get;set;} //Mapped to ColumnC in Table 1 } B and C only map extra properties which are column projections. CreateCriteria(typeof(A)).Add(Expression.Eq("Id", 5)).UniqueResult<A>() CreateCriteria(typeof(C)).Add(Expression.Eq("Id", 5)).UniqueResult<C>() The Database Identity of A and C are the same. The only difference is that C includes C.AProperty, C.BProperty, and C.CProperty projection. Where as A only has A.AProeprty projection. Thanks, Brian On Oct 22, 7:54 am, Fabio Maulo <[email protected]> wrote: A row in the DB is the representation of the state of one object: which one? -- Fabio Maulo El 22/10/2010, a las 11:40, Brian Chavez <[email protected]> escribió: Hi Alan, Thanks so much for the reply. I'm trying to avoid NHibernate using the database to determine the type of object. A single row in Table 1 can be projected into any object in the class hierarchy. For example, Row 5 is A, B, or C; depending on which type I'm requesting. If I CreateCriteria(typeof(C)), then NHibernate has enough information to know what type I'm requesting. I don't want NHibernate to extract type information from the database (ie: discriminator) because class A, B, and C can all represent any row in Table 1. The only difference between A, B, and C classes is the projections of the columns in the table. I hope that clarifies my situation. Any feedback would be appreciated! -Brian On Oct 22, 7:13 am, "[email protected]" <[email protected]> wrote: You can use formulas as discriminators as opposed to a column. You obviously have some sort of logic that determines the object type? On Oct 22, 9:02 am, Brian Chavez <[email protected]> wrote: Hello. Problem: I have 1 very large table of columns. I have a class hierarchy that represents different projections of the columns of this table. For example: class A{ AProperty{get;set;} //Mapped to ColumnA in Table 1 } class B : A { BProperty{get;set;} //Mapped to ColumnB in Table 1 } class C : B { CProperty{get;set;} } When I ask NHibernate to pull C, I expect to see C.AProperty, C.BProperty, and C.CProperty. Essentially, this class hierarchy represents different scoped projected views of the *same* table. How do I do this in hbm.xml mapping files without adding discriminator values? I've tried to use multiple <union-subclass> attributes and map to the same table, but NH throws an exception: --> NHibernate.DuplicateMappingException : Duplicate table mapping Table 1 Any ideas? Thanks, Brian -- 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 athttp:// groups.google.com/group/nhusers?hl=en. -- 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. -- 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.
