Azure Search - basic search in Czech language

Question

I have an index created in Azure Search service where I have several string fields marked as searchable using Czech - Lucene analyzer. In Czech language we use some accented characters and it is common that people replace accented characters with non-accented when typing. Therefore, for example "Václav" (name) has the same meaning as "Vaclav". In my index, I have few documents with word "Václav" and none with word "Vaclav".

As much as I'd expect that Azure Search would return all documents containing word "Václav" when I search for "Vaclav", it is not the case. I'm wondering if I have to parse the query somehow before sending to the search engine.

I ran my tests both thru Azure Portal (setting API version to 2015-02-28-Preview) and thru my code using the very latest SDK Microsoft.Azure.Search 1.1.1.

Yahnoosh Yahnoosh · Accepted Answer · 2016-04-11T22:54:47

By default Lucene and Microsoft analyzers for the Czech language don't ignore diacritics. The easiest way to achieve what you want is to use standardasciifolding.lucene analyzer instead. Alternatively, you could build a custom analyzer to add the ASCII folding token filter to the standard analysis chain for Czech. For example:

{
  "name":"example",
  "fields":[
    {
      "name":"id",
      "type":"Edm.String",
      "key":true
    },
    {
      "name":"text",
      "type":"Edm.String",
      "searchable":true,
      "retrievable":true,
      "analyzer":"my_czech_analyzer"
    }
  ],
  "analyzers":[
    {
      "name":"my_czech_analyzer",
      "@odata.type":"#Microsoft.Azure.Search.CustomAnalyzer",
      "tokenizer":"standard",
      "tokenFilters":[
        "lowercase",
        "czech_stop_filter",
        "czech_stemmer",
        "asciifolding"
      ]
    }
  ],
  "tokenFilters":[
    {
      "name":"czech_stop_filter",
      "@odata.type":"#Microsoft.Azure.Search.StopTokenFilter",
      "stopwords_list":"_czech_"
    },
    {
      "name":"czech_stemmer",
      "@odata.type":"#Microsoft.Azure.Search.StemmerTokenFilter",
      "language":"czech"
    }
  ]
}

We realize that the experience is not optimal now. We’re working to make customizations like this easier.

Let me know if this answers your question

Azure Search - basic search in Czech language

1 Answers