# Few questions about analyzers, mappings and queries in the context of search for substrings **URL:** \ **Category:** Elasticsearch\ **Created:** [September 24, 2012, 12:03pm UTC](https://discuss.elastic.co/t/few-questions-about-analyzers-mappings-and-queries-in-the-context-of-search-for-substrings/9115 "2012-09-24T12:03:39Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![GianMaria\_Romanato](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@GianMaria\_Romanato](https://discuss.elastic.co/u/GianMaria_Romanato)\ **Post date:** [September 24, 2012, 12:03pm UTC](https://discuss.elastic.co/t/few-questions-about-analyzers-mappings-and-queries-in-the-context-of-search-for-substrings/9115/1 "2012-09-24T12:03:39Z")
Ciao all, I spent the last few hours studying ElasticSearch documentation, reading posts in this group and searching Stackoverflow and over the Web in general. I manage to search for substrings as follows: - created an empty index - defined index analysis settings to use a a custom analyzer that uses an nGram filter - defined mappings for an index and type specifying the above analyzer for each property - posted some documents to the right index and type Everything works as expected, but I still have some doubts: 1. the elasticsearch documentation states that the mappings definition is not needed in general ([http://www.elasticsearch.org/guide/reference/mapping/](http://www.elasticsearch.org/guide/reference/mapping/)), but in my tests search for substrings did not work without mappings. Is this the case or there is a mistake in my code and search for substrings should work without mappings? 2. is there a way to define mappings that apply to all the types in an index? 3. search for substring works, but only if I am specifying the field name in the query (curl "[http://localhost:9200/1/\_search?q=description:desc](http://localhost:9200/1/_search?q=description:desc)" ), while a text query returns no hits (curl "[http://localhost:9200/1/\_search?q=desc](http://localhost:9200/1/_search?q=desc)"). Why? 4. I created the index and specified settings and mappings using CURL. When using the Java API is it correct to use the exact same JSON below as the input of ImmutableSettings.Builder.loadFromSource() ? Here are the settings and mappings I used: { "settings":{ "index":{ "analysis":{ "analyzer":{ "my\_analyzer":{ "type":"custom", "tokenizer":"lowercase", "filter":[ "my\_ngram" ] } }, "filter":{ "my\_ngram":{ "type":"nGram", "min\_gram":3, "max\_gram":20 } } } } }, "mappings":{ "overview":{ "properties":{ "title":{ "type":"string", "analyzer":"my\_analyzer", "boost" :10 }, "description":{ "type":"string", "analyzer":"my\_analyzer", "boost":10 }, "id":{ "type":"string", "analyzer":"my\_analyzer", "boost":10 }, "author":{ "type":"string", "analyzer":"my\_analyzer", "boost":10 }, } } } } Thanks in advance. GianMaria. -- ---
**Author:** ![GianMaria\_Romanato](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@GianMaria\_Romanato](https://discuss.elastic.co/u/GianMaria_Romanato)\ **Post date:** [September 24, 2012, 2:56pm UTC](https://discuss.elastic.co/t/few-questions-about-analyzers-mappings-and-queries-in-the-context-of-search-for-substrings/9115/2 "2012-09-24T14:56:10Z")
I have another question: I splitted the settings and mappings in two json files, because I would like the mappings to be applied to several index types whose names are not known in advance. So I am creating an index specifying only the settings and then, the first time a new type is used I am creating a putmappingrequest to pass the mapping for that index type. However, this approach fails, because the analyzer is defined in the settings but when I try to provide mappings for the index type the parser cannot resolve the analyzer: org.elasticsearch.index.mapper.MapperParsingException: Analyzer [my\_analyzer ] not found for field [title] at org.elasticsearch.index.mapper.core.TypeParsers.parseField( TypeParsers.java:74) ~[elasticsearch-0.19.8.jar:na] at org.elasticsearch.index.mapper.core.StringFieldMapper$TypeParser. parse(StringFieldMapper.java:116) ~[elasticsearch-0.19.8.jar:na] at org.elasticsearch.index.mapper.object.ObjectMapper$TypeParser. parseProperties(ObjectMapper.java:261) ~[elasticsearch-0.19.8.jar:na] at org.elasticsearch.index.mapper.object.ObjectMapper$TypeParser.parse( ObjectMapper.java:217) ~[elasticsearch-0.19.8.jar:na] at org.elasticsearch.index.mapper.DocumentMapperParser.parse( DocumentMapperParser.java:161) ~[elasticsearch-0.19.8.jar:na] at org.elasticsearch.index.mapper.MapperService.parse(MapperService.java :271) ~[elasticsearch-0.19.8.jar:na] at org.elasticsearch.cluster.metadata.MetaDataMappingService$4.execute( MetaDataMappingService.java:317) ~[elasticsearch-0.19.8.jar:na] at org.elasticsearch.cluster.service.InternalClusterService$2.run( InternalClusterService.java:211) ~[elasticsearch-0.19.8.jar:na] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor. java:1110) ~[na:1.7.0\_07] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor .java:603) ~[na:1.7.0\_07] Any idea? Giamma. -- ---
**Author:** ![Ivan](https://avatars.discourse-cdn.com/v4/letter/i/df788c/32.png) [@Ivan](https://discuss.elastic.co/u/Ivan)\ **Post date:** [September 25, 2012, 8:03pm UTC](https://discuss.elastic.co/t/few-questions-about-analyzers-mappings-and-queries-in-the-context-of-search-for-substrings/9115/3 "2012-09-25T20:03:40Z")
Hi GianMaria, Answers inline. On Mon, Sep 24, 2012 at 5:03 AM, GianMaria Romanato [gm.romanato@gmail.com](mailto:gm.romanato@gmail.com) wrote: > the elasticsearch documentation states that the mappings definition is not > needed in general ([Elasticsearch Platform — Find real-time answers at scale | Elastic](http://www.elasticsearch.org/guide/reference/mapping/)), > but in my tests search for substrings did not work without mappings. Is this > the case or there is a mistake in my code and search for substrings should > work without mappings? Elasticsearch will work without an explicit mapping, but only with the default behavior. That same webpage states: "Only when the defaults need to be overridden must a mapping definition be provided.". Searching by substring is definitley not the default. > is there a way to define mappings that apply to all the types in an index? Not sure, but take a look at index templates. Perhaps the type name can be a wildcard. > **[Elasticsearch Platform — Find real-time answers at scale](https://www.elastic.co)** > > Power insights and outcomes with the Elasticsearch Platform and AI. See into your data and find answers that matter with enterprise solutions designed to help you build, observe, and protect. Try Elasticsearch free today. > search for substring works, but only if I am specifying the field name in > the query (curl "[http://localhost:9200/1/\_search?q=description:desc](http://localhost:9200/1/_search?q=description:desc)" > ), while a text query returns no hits (curl > "[http://localhost:9200/1/\_search?q=desc](http://localhost:9200/1/_search?q=desc)"). Why? Queries with no field specified will use the \_all field, which uses the default analyzer. > **[Elasticsearch Platform — Find real-time answers at scale](https://www.elastic.co)** > > Power insights and outcomes with the Elasticsearch Platform and AI. See into your data and find answers that matter with enterprise solutions designed to help you build, observe, and protect. Try Elasticsearch free today. > I created the index and specified settings and mappings using CURL. When > using the Java API is it correct to use the exact same JSON below as the > input of ImmutableSettings.Builder.loadFromSource() ? Never tried to use JSON with Java. Cheers, Ivan -- ---
**Author:** ![GianMaria\_Romanato](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@GianMaria\_Romanato](https://discuss.elastic.co/u/GianMaria_Romanato)\ **Post date:** [September 28, 2012, 3:41pm UTC](https://discuss.elastic.co/t/few-questions-about-analyzers-mappings-and-queries-in-the-context-of-search-for-substrings/9115/4 "2012-09-28T15:41:13Z")
Hi Ivan, thank you very much for your helpful reply, it clarified some of my doubts. I did not try your suggestion of using templates because I managed to create the mapping on demand using the Java API and a template JSON document. In fact, with respect to my last question about JSON, I confirm that it is possible to set the type mapping or the index settings using a JSON document via the Java API. However, due to lack of good examples, I found a bit difficult to create correct JSON documents. So after a couple of unsuccessful tries, I decided to first create an index and a type with default settings and auto-generated mapping. Then I used the \_settings and \_mapping REST API to enquiry for the configuration, and the reponse messages helped me figure out how to write a correct JSON document for the index settings and a second JSON document for the type mapping. Again, thank you for your help. Giamma. -- ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 3:10am UTC](https://discuss.elastic.co/t/few-questions-about-analyzers-mappings-and-queries-in-the-context-of-search-for-substrings/9115/5 "2017-07-06T03:10:50Z")