Question

Based on this article from Ayende i have created the following index definition

public class ProductsSearch : AbstractIndexCreationTask<Product, ProductsSearch.Result>
{
    public class Result
    {
        public string Query { get; set; }
    }

    public ProductsSearch()
    {
        Map = products => from product in products
                          select new
                          {
                              Query = new object[]
                              {
                                  product.Title,
                                  product.Tags.Select(tag => tag.Name),
                                  product.Tags.SelectMany(tag => tag.Aliases, (tag, alias) => alias.Name)
                              }
                          };

        Index(x => x.Query, FieldIndexing.Analyzed);
    }
}

One difference is that i must use a SelectMany statement to get the aliases of a tag.
A tag can have many aliases (i. e. tag: mouse alias:pointing device)

I have no idea why the SelectMany line breaks the index. If i remove it, the index works.

Answer 1

This should work:

Map = products => from product in products
                  from tag in product.Tags
                  from alias in tag.Aliases
                      select new
                      {
                          Query = new object[]
                          {
                              product.Title,
                              tag.Name,
                              alias.Name
                          }
                      };