1

I have a grid and I need to support full text search. I need to support search not only by start with and end with, but I need to support search by the part of word. For example if I have "MyWord", I need that search will found by the part of "wor". If I try to use string.contains() I get the following error:

Contains is not supported, doing a substring match over a text field is a very slow operation, and is not allowed using the Linq API.
The recommended method is to use full text search (mark the field as Analyzed and use the Search() method to query it.

If I build raven db index and mark field as Analyzed, contains is not working. It works with StartWith() and EndWith(), but not with contains. Using .Search() I'm getting the same results. Another option is to use lucene syntax:

.Where("Name:*partOfWord*")

and it works fine, but I don't want to combine linq with lucene syntax and I want to solve it using raven db indexes.

Have you any ideas how to implement full text search for raven db using indexes?

Algirdas
  • 1,065
  • 1
  • 9
  • 21

2 Answers2

2

You want to be using an NGram analyzer, as described here. It's an analyzer you can add to your RavenDB server by dropping its DLL in the Analyzers folder.

You really don't want to do any *substr Lucene queries ("ending with" clauses, that is), because the performance is terrible. The inconsistency in coding style is a lesser problem.

Community
  • 1
  • 1
Hannes Johansson
  • 1,794
  • 2
  • 15
  • 28
1

I use this query to search for persons full names by just typing a part of the name. It is recommended to set a minimum length of search string.

.Search(x => x.Name, "word to search" + "*", escapeQueryOptions: EscapeQueryOptions.AllowPostfixWildcard)
user1797792
  • 1,169
  • 10
  • 26
  • This will only match if the names *start* with the string, right? – Hannes Johansson Apr 14 '13 at 12:44
  • I thought the same, but it works both ways for me. I use it for autocomplete on a website. – user1797792 Apr 14 '13 at 12:46
  • You don't mean that it matches *terms* that starts with the word? Because, say I index my name, Hannes Johansson, and analyze it in the index. Then I will have the two terms "Hannes" and "Johansson". So if I query for "Joha*" or "Han*" it will match, but if I query for "hansson*" it won't match. – Hannes Johansson Apr 14 '13 at 12:49