How to use NHibernate's ICriteria for grouping, fetching associations and T-SQL functions

Question

I want to create the following T-SQL statement:

SELECT  SUM (sa.Amount) as 'SumAmount',
        SUM(sa.Cost) as 'SumCost', 
        gg.[Description] as 'Goodsgroup', Month(sa.[Date]) as 'Month' 
FROM SalesmanArticle sa
INNER JOIN Article a
    ON a.ArticleId = sa.ArticleId
INNER JOIN GoodsGroup gg
    ON gg.GoodsGroupId = a.GoodsGroupId
GROUP BY gg.[Description], Month(sa.[Date])
ORDER BY 'Month', 'Goodsgroup'

Is this possible with NHibernates ICriteria?

How can I use the Month-T-SQL-Function?

Do I have to join manually or does the ICriteria API knows that when I use the propetyName 'SalesmanArticle.Article.Goodsgroup.Description' it has to join the Article and the Goodsgroup?

EDIT:

For now I have written this code here:

// typesafe properties
string article = typeof(Article).Name;
string goodsGroup = typeof(GoodsGroup).Name;
string salesmanArticle = typeof(SalesmanArticle).Name;

string amount = Reflector.GetPropertyName<SalesmanArticle>(x => x.Amount);
string cost = Reflector.GetPropertyName<SalesmanArticle>(x => x.Cost);
string description = string.Format("{0}.{1}",
    goodsGroup, Reflector.GetPropertyName<SalesmanArticle>(x => x.Article.GoodsGroup.Description));
string date = Reflector.GetPropertyName<SalesmanArticle>(x => x.Date);

string formatedDate = string.Format("MONTH([{0}])", date);

return GetSession()
    // FROM
    .CreateCriteria(typeof(SalesmanArticle), salesmanArticle)
    // JOIN
        .CreateCriteria(article, article, JoinType.InnerJoin)
        .CreateCriteria(goodsGroup, goodsGroup, JoinType.InnerJoin)
    // SELECT
        .SetProjection(Projections.ProjectionList()
                           .Add(Projections.Sum(amount))
                           .Add(Projections.Sum(cost))
    // GROUP BY
                           .Add(Projections.GroupProperty(description))
                           .Add(Projections.SqlGroupProjection(formatedDate, formatedDate, new[]{"MyDate"} , new[] { NHibernateUtil.Int32 })))
        .List();

But an AdoException is thrown:

could not execute query [ SELECT sum(this_.Amount) as y0_, sum(this_.Cost) as y1_, goodsgroup2_.Description as y2_, MONTH([Date]) FROM [SalesmanArticle] this_ inner join [Article] article1_ on this_.ArticleId=article1_.ArticleId inner join [GoodsGroup] goodsgroup2_ on article1_.GoodsGroupId=goodsgroup2_.GoodsGroupId GROUP BY goodsgroup2_.Description, MONTH([Date]) ]

[SQL: SELECT sum(this_.Amount) as y0_, sum(this_.Cost) as y1_, goodsgroup2_.Description as y2_, MONTH([Date]) FROM [SalesmanArticle] this_ inner join [Article] article1_ on this_.ArticleId=article1_.ArticleId inner join [GoodsGroup] goodsgroup2_ on article1_.GoodsGroupId=goodsgroup2_.GoodsGroupId GROUP BY goodsgroup2_.Description, MONTH([Date])]

The strange thing is that NHibernate tries to create 2 queries?!

AND BOTH of them are correct!

Instead of the codeline

.Add(Projections.SqlGroupProjection(formatedDate, formatedDate, new[]{"MyDate"} , new[] { NHibernateUtil.Int32 })))

I used

.Add(Projections.SqlFunction("MONTH", NHibernateUtil.Int32, Projections.GroupProperty(date))))

The problem with the SqlFunction is that it creates a GROUP BY sa.Date instead of MONTH(sa.Date). But this method worked syntactically correct.

So I switched to the SqlGroupProjection method.

But anyway it does not work.

Can anybody help me?

Answer 1

I solved it. Here is the correct code:

public class SalesmanArticleRepository : Repository<SalesmanArticle>, ISalesmanArticleRepository
{
    public IList GetAllAll()
    {
        // typesafe properties
        string article = typeof(Article).Name;
        string goodsGroup = typeof(GoodsGroup).Name;
        string salesmanArticle = typeof(SalesmanArticle).Name;

        string amount = Reflector.GetPropertyName<SalesmanArticle>(x => x.Amount);
        string cost = Reflector.GetPropertyName<SalesmanArticle>(x => x.Cost);
        string description = string.Format("{0}.{1}",
            goodsGroup, Reflector.GetPropertyName<SalesmanArticle>(x => x.Article.GoodsGroup.Description));
        string date = Reflector.GetPropertyName<SalesmanArticle>(x => x.Date);

        string formatedDateSql = string.Format("month({{alias}}.[{0}]) as mydate", date);
        string formatedDateGroupBy = string.Format("month({{alias}}.[{0}])", date);

        return GetSession()
            // FROM
            .CreateCriteria(typeof(SalesmanArticle), salesmanArticle)
            // JOIN
                .CreateCriteria(article, article, JoinType.InnerJoin)
                .CreateCriteria(goodsGroup, goodsGroup, JoinType.InnerJoin)
            // SELECT
                .SetProjection(Projections.ProjectionList()
                                   .Add(Projections.Sum(amount))
                                   .Add(Projections.Sum(cost))
            // GROUP BY
                                   .Add(Projections.GroupProperty(description))
                                   .Add(Projections.SqlGroupProjection(formatedDateSql, formatedDateGroupBy, new[] { "mydate" }, new[] { NHibernateUtil.Int32 })))
                .List();
    }
}