Update one table using data correlated from another table

I need to replicate the following statement in Lightspeed (using the UnitOfWork.Update method). Just wondering what the syntax would be

DECLARE @p0 nvarchar(5)
DECLARE @p1 nvarchar(11)
DECLARE @p2 bit
DECLARE @p3 datetime

SELECT @p0=N'en-NZ'
SELECT @p1=N'50Plibabcd1'
SELECT @p2=1
SELECT @p3='2013-05-22 15:12:46.300'

UPDATE
  [Document]
SET
  [DocumentContentDate] = @p3
FROM [Document] INNER JOIN [DocumentRelation] ON [DocumentRelation].DestinationDocumentId = [Document].ParliamentDocumentId
WHERE
  (([Document].[CmsLanguage] = @p0 AND [DocumentRelation].[SourceDocumentId] = @p1) AND [DocumentRelation].[Reciprocal] = @p2);
GO

I tried the following, but it didn't output the join as I expected var language = document.Language; var parliamentDocumentId = document.ParliamentDocumentId; var pCmsLanguage = Mindscape.LightSpeed.Entity.Attribute("cmsLanguage"); var pSourceDocumentId = Mindscape.LightSpeed.Entity.Attribute("sourceDocumentId"); var pReciprocal = Mindscape.LightSpeed.Entity.Attribute("reciprocal");

        var query = new Query(typeof(Document))
        {
            Join = Join.Inner<Document, DocumentRelation>("parliamentDocumentId", "destinationDocumentId"),
            QueryExpression = pCmsLanguage == language
                                && pSourceDocumentId == parliamentDocumentId
                                && pReciprocal == true
        };

        _unitOfWork.Update(query, new { DocumentContentDate = dateTime });

Rather than specifying the join you will want to specify the associations as part of the Entity.Attribute specifications,

e.g.

var query = new Query(typeof(Document))
{
  QueryExpression = Entity.Attribute("cmsLanguage") == language
                    && Entity.Attribute("DocumentRelations.sourceDocumentId") == parliamentDocumentId
                    && Entity.Attribute("DocumentRelations.reciprocal") == true
};

This will generate a SQL statement with an EXISTS clause but it should match the result you are looking for.

Jeremy