---
title: "nhibernate: count av childcollection"
type: "forum-thread"
url: "https://www.webforum.nu/amne/dotnet/168315-nhibernate-count-av-childcollection"
topic: ".NET"
topic_url: "https://www.webforum.nu/amne/dotnet"
author: "doggelito"
published: "2008-01-22T09:15:50.000Z"
updated: "2008-01-22T15:42:06.000Z"
replies: 1
views: 304
page: 1
pages: 1
language: "sv-SE"
site: "webForum — webforum.nu"
rights: "Upphovsrätten till varje inlägg tillhör dess författare."
attribution: "Citera som: webForum, https://www.webforum.nu/amne/dotnet/168315-nhibernate-count-av-childcollection"
---

# nhibernate: count av childcollection

## #1 — doggelito, 2008-01-22T09:15Z

Hur gör jag för att räkna hur många produkter en kategori har utan att köra ex.
categories\[0\].Products.Count?
Det känns ju onödigt att instansiera produktsamlingen bara för detta.

```
IList<Category> categories = session.CreateCriteria(typeof(Category)).List<Category>();
```

```
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
   <class name="Swh.Entities.Category, Swh.Entities" table="Categories">
      <id name="Id" column="CategoryId" type="int" unsaved-value="-1">
         <generator class="identity" />
      </id> 
      <property name="Name" column="CategoryName" type="String"/>
      <bag name="Products">
         <key column="CategoryId"/>
         <one-to-many class="Swh.Entities.Product, Swh.Entities"/>
      </bag>
   </class>
</hibernate-mapping>

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
   <class name="Swh.Entities.Product, Swh.Entities" table="Products">
      <id name="Id" column="ProductId" type="int" unsaved-value="-1">
         <generator class="identity" />
      </id>
      <property name="Name" column="ProductName" type="String"/>
      <many-to-one name="Category" class="Swh.Entities.Category, Swh.Entities" column="CategoryId" />
   </class>
</hibernate-mapping>
```

Permalänk: https://www.webforum.nu/p/168315

## #2 — doggelito, 2008-01-22T15:42Z

Fixat!
La till en property i min Categorimappning.

```
<property name="ProductCount" formula="(select count(*) from Products p where p.CategoryId = CategoryId )" access="property"/>
```

Permalänk: https://www.webforum.nu/p/2074991

---

Tråden på webben: https://www.webforum.nu/amne/dotnet/168315-nhibernate-count-av-childcollection