EF Core freetext with child entity

Question

EF Core 2.1 has added support for FREETEXT, as also discussed in How to use FreeText in EF core 2.1. I have a different problem, however, using EF Core 2.2: Does EF Core's FREETEXT support child entities?

public class Customer
{
    public Name Name { get; set; }

    public List<Address> Addresses { get; set; }
}

Name is an owned entity (value object), which works perfectly for searching:

public class Name
{
    public string FirstName { get; set; }

    public string LastName { get; set; }
}

Address is a child entity:

public class Address
{
    public string Street { get; set; }

    public string Number { get; set; }
}

This search works fine:

query.Where(c => EF.Functions.Freetext(c.Name.FirstName, searchTerm) || EF.Functions.Freetext(c.Name.LastName, searchTerm)

This search does not, as the final term cannot be translated to SQL:

query.Where(c => EF.Functions.Freetext(c.Name.FirstName, searchTerm) || EF.Functions.Freetext(c.Name.LastName, searchTerm) || EF.Functions.Freetext(c.Addresses.First().Street, searchTerm)

Is there any way around this, or will I need to use a SQL function? I've tried using a Select() statement, but that could also not be fully translated to SQL.

Answer 1

Found it! Apparently, EF.Functions.FreeText(c.Addresses.First().Street, searchTerm) cannot be evaluated client-side. However, this can:

EF.Functions.FreeText(c.Addresses.Any(a => EF.Functions.FreeText(a.Street, searchTerm))

So make sure EF.Functions.FreeText() receives a simple string as its first property, and use any other LINQ for selecting the First(), 'Last()', Any() and All() of child entities.