How to call a procedure using NHibernate that returns result from multiple tables?
Normally we create 1:1 mapping per table-class.
Ex(开发者_JS百科Tables):
[users] user_id - PK name [transactions] user_id - FK item_id amount Example mapping: public class User { public string ID {get; set;} public string Name {get; set;} } public class Transaction { public string UserID {get; set;} public string ItemID {get; set;} public Decimal Amount {get; set;} } But due to optimization concern and sometimes there are operations needed to be done while querying for results; we usually use stored procedures that returns result from multiple tables. If we use the example above; how can we call a procedure that returns results from the joined tables? Is it possible without creating a new class and binding just for the sake of this combined records?Thanks!
It is possible to use a stored procedure in this case, using a mapping construct like the following:
<sql-query name="LoadUsersAndTransactions" xml:space="preserve">
<return class="User" alias="u">
<return-property name="ID" column="user_id" />
<return-property name="Name" column="name" />
</return>
<return-join property="u.Transactions" alias="t">
<return-property name="key" column="user_id" />
<return-property name="element" column="item_id" />
<return-property name="element.id" column="item_id" />
<return-property name="element.Amount" column="amount" />
</return-join>
EXEC dbo.SelectUsersAndTransactions :param_1, ..., :param_N
</sql-query>
This example assumes that Transactions is mapped as a bag on the User class. You would use this query as follows from C#:
IList<User> users = session
.GetNamedQuery("LoadUsersAndTransactions")
.SetString("param_1", parameterValue1)
...
.SetString("param_N", parameterValueN)
.List<User>();
NHibernate documentation on usage of custom SQL queries is here.
Cheers, Gerke.
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