c# - Adding condition to mapping for child collection in Entity Framework 6 similar to NHibernate's "where" -

in nhibernate, there where mapping allows specify condition on property mapping affects how pulled database. example, if wanted implement soft delete , exclude deleted items set, map so:

fluentnhibernate

// in class parentmap : classmap hasmany(x => x.children).where("isdeleted = 0"); 

hbm.xml

<class name="parent" table="[parents]">     <bag cascade="all" lazy="true" name="children" where="isdeleted = 0">         <!-- rest of map here -->     </bag> </class> 

is there similar in entity framework 6?

the closest thing found library called entityframework.filters, allows add global filters properties, doesn't seem work when property collection.

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to give better example of why mapping necessary, let's have class has collection of objects have recursive child entity relationship (i.e., collection of objects of same type). follow basic structure:

public class reportoutline {     public long id { get; set; }     public string title { get; set; }     public string author { get; set; }         public virtual icollection<outlineitem> outlineitems { get; set; } }  public class outlineitem {     public long id { get; set; }     public string name { get; set; }      public long reportoutlineid { get; set; }     public long? parentoutlineitemid { get; set; }          public virtual reportoutline reportoutline { get; set; }     public virtual outlineitem parentoutlineitem { get; set; }          public virtual icollection<outlineitem> outlineitems { get; set; } } 

and these mapped ef fluent api this:

modelbuilder.entity<reportoutline>()     .haskey(o => o.id)     .hasmany(o => o.outlineitems)     .withrequired(i => i.reportoutline)     .hasforeignkey(i => i.outlineid);  modelbuilder.entity<outlineitem>()     .haskey(p => p.id)     .hasmany(p => p.outlineitems)     .withoptional(c => c.parentoutlineitem)     .hasforeignkey(c => c.parentoutlineitemid); 

this produces correct database structure, , records fine. here's example of outlineitems table 2 items on reportoutline, if 1 had 2 child items (four altogether):

id    name           reportoutlineid    parentoutlineitemid 1     introduction   1                  null 2     pets           1                  null 3     cats           1                  2 4     dogs           1                  2 

when reportoutline gets loaded through dbcontext, however, since reportoutlineid matched outline's id, reportoutline.outlineitems getting populated 4 items. results in sub-items appearing both under parent items , main outline itself:

title:  report author: valverij  i.  introduction  (id: 1) ii. pets          (id: 2)     a. cats       (id: 3)     b. dogs       (id: 4) iii. cats         (id: 3) <--- duplicated iv.  dogs         (id: 4) <--- duplicated 

now, if using nhibernate fluentnhibernate, specify where condition on entity mapping, reportoutline.outlineitems only pulls parent items:

// in reportoutlinemap hasmany(x => x.outlineitems).where("parentoutlineitemid null"); 

without that, have remember only access reportoutline objects through pre-written query explicitly deals outlineitem collection.

you add "rootoutlineitems" property reportoutline class filters you, call when want 1st level:

public class reportoutline {     public long id { get; set; }     public string title { get; set; }     public string author { get; set; }         public virtual icollection<outlineitem> outlineitems { get; set; }     public icollection<outlineitem> rootoutlineitems {          {             return outlineitems.where(p=> p.parentoutlineitem == null);         }     } } 

another option make outlineitem's reportoutline nullable, , ever set either reportoutline or parentoutlineitem property, that's little iffy, plus you'd have navigate tree if ever want all items.