NHibernate inattendu Instruction ORDER BY

Question

J'utilise NHibernate 2.0, et lorsque je soumets une requête demandant le retour des 2 premiers enregistrements, j'obtiens un certain nombre de clauses ORDER BY dans mon SQL. Lorsque je supprime les résultats Max, la requête semble correcte (aucune instruction ORDER BY). Pourquoi NHibernate l'ajoute-t-il automatiquement lorsque je cherche un sous-ensemble d'enregistrements? Merci à l'avance

Voir les instructions SQL ci-dessous:

ORDER inattendue PAR

 
exec sp_executesql 
N'SELECT TOP 2 Person1_36_0_, LastReco2_36_0_, SSN3_36_0_, 
FirstName4_36_0_, LastName5_36_0_, MiddleIn6_36_0_, Title7_36_0_, Suffix8_36_0_, 
DateOfBi9_36_0_, IsDeceased10_36_0_, Decease11_36_0_, Contact12_36_0_, MailHol13_36_0_, 
MailHol14_36_0_, MailHol15_36_0_, Preferr16_36_0_, CreatedBy17_36_0_, Created18_36_0_, 
ModifiedBy19_36_0_, Modifie20_36_0_ 
FROM (SELECT ROW_NUMBER() OVER(ORDER BY __hibernate_sort_expr_0__) as row, 
query.Person1_36_0_, query.LastReco2_36_0_, query.SSN3_36_0_, query.FirstName4_36_0_, 
query.LastName5_36_0_, query.MiddleIn6_36_0_, query.Title7_36_0_, query.Suffix8_36_0_, 
query.DateOfBi9_36_0_, query.IsDeceased10_36_0_, query.Decease11_36_0_, 
query.Contact12_36_0_, query.MailHol13_36_0_, query.MailHol14_36_0_, query.MailHol15_36_0_, 
query.Preferr16_36_0_, query.CreatedBy17_36_0_, query.Created18_36_0_, 
query.ModifiedBy19_36_0_, query.Modifie20_36_0_, query.__hibernate_sort_expr_0__ 
FROM 
(SELECT this_.Person_id as Person1_36_0_, this_.[LastRecordVersion] as LastReco2_36_0_, 
this_.[SSN] as SSN3_36_0_, this_.[FirstName] as FirstName4_36_0_, this_.[LastName] as 
LastName5_36_0_, this_.[MiddleInitial] as MiddleIn6_36_0_, this_.[Title] as Title7_36_0_, 
this_.[Suffix] as Suffix8_36_0_, this_.[DateOfBirth] as DateOfBi9_36_0_, this_.[IsDeceased] 
as IsDeceased10_36_0_, this_.[DeceasedDate] as Decease11_36_0_, this_.[ContactMethod_id] as 
Contact12_36_0_, this_.[MailHoldReason_id] as MailHol13_36_0_, this_.[MailHoldStartDate] as 
MailHol14_36_0_, this_.[MailHoldEndDate] as MailHol15_36_0_, this_.[PreferredName] as 
Preferr16_36_0_, this_.[CreatedBy] as CreatedBy17_36_0_, this_.[CreatedDate] as 
Created18_36_0_, this_.[ModifiedBy] as ModifiedBy19_36_0_, this_.[ModifiedDate] as 
Modifie20_36_0_, CURRENT_TIMESTAMP as __hibernate_sort_expr_0__ 
FROM MC_Person this_ 
WHERE this_.[SSN] = @p0) query) page 
WHERE **page.row > 0 ORDER BY __hibernate_sort_expr_0__**', 
N'@p0 nvarchar(9)',@p0=N'123456789' 

SQL correcte (sans obtenir Top 2 records)

 
exec sp_executesql 
N'SELECT this_.Person_id as Person1_36_0_, this_.[LastRecordVersion] as LastReco2_36_0_, 
this_.[SSN] as SSN3_36_0_, this_.[FirstName] as FirstName4_36_0_, this_.[LastName] as 
LastName5_36_0_, this_.[MiddleInitial] as MiddleIn6_36_0_, this_.[Title] as Title7_36_0_, 
this_.[Suffix] as Suffix8_36_0_, this_.[DateOfBirth] as DateOfBi9_36_0_, this_.[IsDeceased] 
as IsDeceased10_36_0_, this_.[DeceasedDate] as Decease11_36_0_, this_.[ContactMethod_id] as 
Contact12_36_0_, this_.[MailHoldReason_id] as MailHol13_36_0_, this_.[MailHoldStartDate] as 
MailHol14_36_0_, this_.[MailHoldEndDate] as MailHol15_36_0_, this_.[PreferredName] as 
Preferr16_36_0_, this_.[CreatedBy] as CreatedBy17_36_0_, this_.[CreatedDate] as 
Created18_36_0_, this_.[ModifiedBy] as ModifiedBy19_36_0_, this_.[ModifiedDate] as 
Modifie20_36_0_ 
FROM MC_Person this_ 
WHERE this_.[SSN] = @p0', 
N'@p0 nvarchar(9)',@p0=N'123456789' 

Answer 1

Il est la façon dont la pagination est implémentée. Il n'y a donc pas de cas particulier pour prendre les n premiers éléments, car par exemple Oracle ne supporte pas cette construction.

Ainsi, tout ce qui a l'une des limites de pagination est défini de cette façon.

Obtenez-vous les bons résultats?

Answer 2

Une sélection haut ne fait pas beaucoup de sens sans ordre, puisque la commande pourrait changer par la maintainance databasetable.

Ne vous en quelque sorte, définir quel genre de deux meilleurs résultats que vous voulez? d'où l'ordre par?