Question

I am using Linq-To-Sql to populate my business layer. Here is a snippet of a query I am working on:

fund.FundEntities = fundGroup.tFunds
    .Select(fe =>
    {
        var fundEntity = new FundEntity()
        {
            BankAccount = null,
            CloseDate = fe.closeDate ?? new DateTime(),
            Commitment = fe.commitment ?? 0,
            CommitmentEndDate = fe.closeDate ?? new DateTime(),
            Fund = fund
        };
        fundEntity.CapitalCalls = fe.tCapitalCalls
            .Select(cc =>
            {
                return new CapitalCall()
                {
                    Amount = cc.agrAmount ?? 0,
                    FundEntity = fundEntity
                };
            }
             );
        return fundEntity;
    });

When I run this code, it executes queries for individual CapitalCalls at runtime. Is there anyway I could re-architect this to keep the same business object structure (IE- the relations from Fund -> FundEntity -> CapitalCall within the business objects), but load full tables at a time? Ideally, there would be a single SQL query with lots of joins that would result in a fully populated Fund.

Answer 1

var fund = GetFund();
var fundGroup = GetFundGroup();
var dataContest = GetDataContext();


List<int> feIds = fundGroup.tFunds.Select(fe => fe.FundEntityId).ToList();

 //before: iterate through local collection fundGroup.tFunds
 //  and issue one CapitalCall query per fundEntity.
 //after: send all the fundEntityIds into the database in one query
 //  that also fetches related CapitalCalls.
var query =
  from fe in dataContext.tFunds
  where feIds.Contains(fe.FundEntityId))
  let capitalCalls = fe.tCapitalCalls
  select new {FundEntity = fe, CapitalCalls = capitalCalls.ToList() };

foreach(var record in query)
{
  FundEntity fundEntity = new FundEntity()
  {
    CloseDate = record.fe.closeDate ?? new DateTime(),
    ...
  }
  fundEntity.CapitalCalls = ...
}