NHibernate - query specific columns and return distinct records?
I am new to NH.
I have a table in a legacy DB that looks like this:
Id,
CompanyId,
Description,
[LOADS of other columns here]
I would like to return a DISTINCT set of data using NHibernate, selecting only specific columns and using a WHERE statement. The SQL would looks something like this:
SELECT DISTINCT
[table_name].CompanyId,
[table_name].Description
FROM
[table_name]
WHERE
[table_name].CompanyId = 2
Having googled this I came up with:
ProjectionList projections = Projections.ProjectionList();
projections.Add(Projections.Property("CompanyId"), "CompanyId");
projections.Add(Projections.Property("Name"), "SomeName");
var companyDto = session.QueryOver<Company>()
.Where(x => x.CompanyId == 2)
.Select(projections)
.TransformUsing(Transformers.AliasToBean<CompanyDto>())
.List<CompanyDto>();
if (companyDto != null)
Console.WriteLine(string.Format("{0}, {1}", companyDto.CompanyId, companyDto.SomeName));
Where the DTO is:
public class CompanyDto
{
public int CompanyId { get; set; }
public string SomeN开发者_Python百科ame { get; set; }
}
And the entity is:
public class Company
{
public virtual int Id { get; private set; }
public virtual int CompanyId { get; set; }
public virtual string Name { get; set; }
}
This does not bring back disinct records. I know that normally I would have to use a different transform (DistinctRootEntity) but I cannot use two transforms. How can I combine all of the things I want, into a single call? It must be possible, its basic SQL ....
I need to:
- not use HQL
- not bring back all columns for the record
- not bring back duplicate rows
there is a Projection for this
var projections = Projections.Distinct(Projections.ProjectionList()
.Add(Projections.Property("CompanyId").As("CompanyId"))
.Add(Projections.Property("Name").As("SomeName"));
精彩评论