entity framework - Materializing an ICollection structure containing subclasses -

i'm reviewing code written in ef 4 days because stands out during performance benchmarking.

the purpose of code materialize icollection<mybaseclass> using entity framework (we're on ef 6.1).

the code exists because references present in specific subclasses aren't materialized when retrieving

public parent {     public virtual icollection<mybaseclass>() base { get; set; } } 

from database, when actual types stored subclasses of mybaseclass.

example subclass:

public suba : mybaseclass {     public virtual icollection<options> ref1 { get; set; } } 

currently, code this:

var parent = ctx.parents.include(p => p.base).where(...).single(); loadsubclasses(parent.base); ... private void loadsubclasses(ienumerable<mybaseclass> mybase) {     foreach (var in mybase)     {         if (my suba)         {             this.entry(my).reference("ref1").load();             this.entry((suba)my).ref1).collection("options").load();         }         else... // similar other subclasses     } } 

note icollection<mybaseclass>() base contains mix of several concrete subclasses. there few hundred objects in icollection.

is there more efficient way materialize base?

it cannot said in advance if performance better (sometimes executing single complex query, sub collection includes may have negative impact), can minimize number of database queries k, k number of subclass types need additional includes.

you need base loadsubclasses method on iqueryable<tbase> representing base entities, , execute 1 query per each subclass type using oftype filter:

private void loadsubclasses(iqueryable<mybaseclass> basequery) {     // suba     basequery.oftype<suba>()         .include(x => x.ref1.options)         .load();    // similar other subclasses } 

the usage sample be:

var parent = ctx.parents.include(p => p.base).where(...).single(); loadsubclasses(ctx.entry(parent).collection(p => p.base).query()); 

or more generally:

var parentquery = ctx.parents.where(...); var parents = parentquery.include(p => p.base).tolist(); loadsubclasses(parentquery.selectmany(p => p.base));