Nhibernate - How to debug “Antlr.Runtime.NoViableA

Question

With many HQL queries, time and time again I am getting this exception:

Antlr.Runtime.NoViableAltException

This is really generic and unhelpful - does anyone know how best to debug this? Obviously it's a problem with my HQL - but without any clue as to what exactly is wrong it's very much a case of trial and error. I'm pulling my hair out every time I see this.

Note, I don't want to post any HQL here, becuase it's something that I am often coming across, not a problem related to one query.

Does anyone know the best way to tackle this? Is there any tool for validating HQL queries?

Answer 1

Have a look at NHibernate Query Analyzer. It is not perfect, but it will be helpful in many situations.

Answer 2

For instance, if you have the following error:

Exception of type 'Antlr.Runtime.NoViableAltException' was thrown. near line 1, column
745 [select afe.AFEDataId, afe.Name, afe.AdditionalDescription, afe.ProjectType, 
afe.BusinessUnit, afe.plantId, afe.fuelTypeId, afe.DisplayStatus, afe.BudgetedAmount, 
sum(exp.Amount), afe.CreatedDate from Company.AFE.Model.AFEData as afe inner join 
afe.Expenditures as exp inner join exp.ExpenditureType  where (afe.Status.StatusId = 
:statusId) and (afe.IsRestrictedVisibility = false OR (select count(AFEDataId) from 
Company.AFE.Model.Reader as r where r.AFEData.AFEDataId = afe.AFEDataId AND 
r.Contact.ContactId = '70bc6350-c466-40d5-a067-9d1f00bed7dc') > 0 OR (select count(AFEDataId) 
from Company.AFE.Model.Editor as e where e.AFEData.AFEDataId = afe.AFEDataId AND 
e.Contact.ContactId = '70bc6350-c466-40d5-a067-9d1f00bed7dc') > 0 OR 1=1)  afe.AFEDataId, 
afe.Name, afe.AdditionalDescription, afe.ProjectType, afe.BusinessUnit, afe.plantId, 
afe.fuelTypeId, afe.DisplayStatus, afe.BudgetedAmount, afe.CreatedDate  order by afe.Name ASC]

Go and look at character 745 from the original query that was provided and check to see if there is a spelling error, as there was in this one that I just looked at.

Answer 3

I can't help you directly, here's something I can share.

When dealing with hibernate or nhibernate (NH), I generally debug by enabling logging on the nhibernate's log4net, or/and the logging of queries at the DB side (e.g. mysql).

They can tell me what is the queries being formulated and executed at the DB and what are the exceptions thrown back by the DB.

Answer 4

Which version of NH you used, for the latest version, the query exchange has some updated, such as you can't use "count(1)" in query, must change to count([alias name]), NH will translate to "select class.id from ... "