Unknown column 't1.Discriminator' in 'where clause'

Hello,

Consider the following entities.

class Application : Entity<long> { /* ... */ }
abstract class SecurityToken : Entity<long> { /* ... */ }
[Discriminator(Attribute = "Discriminator", Value = 3)]
class RequestSecurityToken : SecurityToken { /* ... */ }

An application has many security tokens, and a security token can have zero or one application. Consider the following query which returns the application for a token:

string token = "blablablabla"; // parameter
var query = new Query(typeof(Application));
var innerQuery = new Query(typeof(RequestSecurityToken), Entity.Attribute("Token") == token);
innerQuery.Projection.Add("ApplicationId");
query.Join = Join.Inner(typeof(Application), innerQuery, "Id", "ApplicationId");
var entity = UnitOfWork.FindOne<Application>(query);

Which generates the following SQL (for MySQL)

SELECT
  t0.Id AS "t0.Id",
  t0.ConsumerKey AS "t0.ConsumerKey",
  t0.ConsumerSecret AS "t0.ConsumerSecret",
  t0.CreatedOn AS "t0.CreatedOn",
  t0.Description AS "t0.Description",
  t0.LockVersion AS "t0.LockVersion",
  t0.Name AS "t0.Name",
  t0.PartyId AS "t0.PartyId",
  t0.UpdatedOn AS "t0.UpdatedOn",
  t0.ValidFrom AS "t0.ValidFrom",
  t0.ValidTo AS "t0.ValidTo",
  t0.VerificationCodeFormat AS "t0.VerificationCodeFormat",
  t0.VerificationCodeLength AS "t0.VerificationCodeLength"
FROM
  Applications t0
INNER JOIN
  (SELECT
    SecurityTokens.ApplicationId
  FROM
    SecurityTokens
  WHERE
    ((SecurityTokens.Token = 'blablablabla' AND SecurityTokens.Discriminator = 3) AND (SecurityTokens.ValidFrom < '1/26/2012 00:18:02' AND SecurityTokens.ValidTo > '1/26/2012 00:18:02'))
  ) t1
ON
  t0.Id = t1.ApplicationId
WHERE
  t1.Discriminator = 3 AND
  (t0.ValidFrom < '1/26/2012 00:18:02' AND t0.ValidTo > '1/26/2012 00:18:02')

Which results in a MySQL error:

Unknown column 't1.Discriminator' in 'where clause'

My query looks correct, however, I'm not 100% sure. I'm not sure why the where clause has the t1.Discriminator = 3 expression. I'd appreciate any suggestions.

Thanks, Werner

It's a bug where the discriminator from the inner query (on RequestSecurityToken) is incorrectly being applied to the outer query as well. We can investigate this if required, but a much easier way to do it is to use a dotted path:

var application = uow.FindOne<Application>(Entity.Attribute("SecurityTokens.Token") == token);

(There is one difference in this query in that it will return the application for which any SecurityToken matches token, not just for which a RequestSecurityToken matches. If that's an issue, I think you can get around it by adding an Entity.Attribute("SecurityToken.Discriminator") == 3 clause though I admit it's not nice to have to explicitly specify the discriminator in the query.)