spring neo4j: how can I search data by index field case insensitive?

问题

Domain class as following:

@NodeEntity
public class Product{

   private Long nodeId;
   @Indexed(indexName = "productCode")
   private String code;
   ...
}

Repository class:

 public interface ProductRepository extends GraphRepository<Product>{       
       @Query(value="start product=node:productCode(code={0}) return product")
        public Set<Product> findProducts(String code);
    }

how can I make code lookup case insensitive? I try regular expression and fail.Code as following:

 public interface ProductRepository extends GraphRepository<Product>{

       @Query(value="start product=node:productCode(code=~{0}) return product")
        public Set<Product> findProducts(String code);
    }

I know one way works but the performance will be not good, the code as following:

 public interface ProductRepository extends GraphRepository<Product>{
       @Query(value="start product=node:__types__(className='Product') where product.code='~{0}' return product")
                public Set<Product> findProducts(String code);
            }