Hey all,

Firstly, I am using:

LLBLGen Pro Version 2.6 Final ( June 6th, 2008 ) - Evaluation Copy

I can itterate through my entity collections, no problem at all... however I have no clue how I can itterate through another entity collection, based on a value returned from an entity inside another collected. That probably is hard to understand, let me try demonstrate...

Here is my current code:

EntityCollection<VmmDriverHistoryEntity> drivers = new EntityCollection<VmmDriverHistoryEntity>(new VmmDriverHistoryEntityFactory()); adapter.FetchEntityCollection(drivers, null); foreach (VmmDriverHistoryEntity driver in drivers) { // do something }

Here is pseudo code for what I want to try do:

EntityCollection<VmmDriverHistoryEntity> drivers = new EntityCollection<VmmDriverHistoryEntity>(new VmmDriverHistoryEntityFactory()); adapter.FetchEntityCollection(drivers, null); foreach (VmmDriverHistoryEntity driver in drivers) { EntityCollection<VmmVehicleEntity> vehicles = new EntityCollection<VmmVehicleEntity>(new VmmVehicleEntityFactory()); adapter.FetchEntityCollection(vehicles, null).Where(driver.VehicleID == vehicles.VehicleID); foreach (VmmVehicleEntity vehicle in vehicles) { // do something } }

I hope it was clear what I am trying to do... if you need me to try better explain myself, please just ask. I've had a look around the documentation, but couldn't find exactly what I'm after.

Regards, Justin

Best thing to do is to use prefetchPaths to fetch drivers with their related vehicles in one go, as follows.

EntityCollection<VmmDriverHistoryEntity> drivers = new EntityCollection<VmmDriverHistoryEntity>();

PrefetchPath2 prefetch = new PrefetchPath2((int)EntityType.VmmDriverHistoryEntity);
prefetchPath.Add(VmmDriverHistoryEntity.PrefetchPathVmmVehicle);

adapter.FetchEntityCollection(drivers, null, prefetch);
foreach (VmmDriverHistoryEntity driver in drivers)
{
     foreach (VmmVehicleEntity vehicle in driver.vehicles)
     {
          // do something
     }
}

Hi Walaa,

Unfortunately I'm having problems with that code. There is no "vehicles" found within "driver" on this line:

foreach (VmmVehicleEntity vehicle in driver.vehicles) {}

I added the PrefetchPath 2 as you demonstrated, but it didn't give me the results, am I perhaps missing something?

Regards, Justin

My code was just for demonstration, so vehicles can be spelled differently.

Please answer the following questions:

1- In LLBLgen Pro designer -> DriverEntity properties -> "fields mapped on relation" tab: is there a vehicles field?

2- In LLBLgen Pro designer -> DriverEntity properties -> relations tab: can you see the "Vehicles" listed there?

3- Is there a relation between these entities in the LLBLGen Pro Designer?

4- Is there a database relation between Vehicles & Drivers? Is there a FK in the Vehicles table that points to the Driver table?

To use a prefetchPath, your answer should be Yes to all of the above questions.

Hi Walaa,

I can answer yes to all 4, and found the name of the object I am after is called "VmmVehicle", however that is a single entity, rather than a collection. Should I be casting it to an IENumerable, or perhaps making a call to a function within it to gain access to the collection, rather than the single entity?

Regards, Justin

Then each driver in VmmDriverHistoryEntity has a relation with only one VmmVehicle. And hence no need for inumeration. am I mkissing something?

Sorry Walaa, in some cases one driver may have multiple vehicles, which is why I was expecting a collection.

Regards, Justin

Must be the relation type, it's 1:1 instead of 1:m. You should check the relation type at your DB and at LLBLGenDesigner. Could you check that? If possible, post the tables DDL code.