If I have a object of class Car that has an nested object of class Engine where both classes have the field named "id" do I have to do anything special when I create the mapping? Or is it sufficient to add the type "nested" to the engine mapping.
Elasticsearch head GUI is showing unexpected rows, but the search seems to give the correct result so it would be good to know if I need to do anything else in the mapping if two or more objects have the same field name.
Seems like the structured query builder returns the engine document with the id that I search for when I select car.id from the dropdown.
There shouldn't be any problem, you can just use the dot notation to refer to the fields in the nested documents.
Also, if you have a single engine per car you don't need to declare the engine as nested in your mapping.
Related
I have a preexisting index that contains field mappings and is currently being queried by many applications. I would like to add additional ways for the data to be queried, specifically, support full text search via analysis. Multi-fields seemed like the obvious way to do this, but I found that adding new multi-fields actually changes the existing query behavior.
For example, I have an "id" field that is a keyword. Applications are already using this field to query on. After I add a new multi-field, like "txt" (using the standard analyzer), new documents can be found by querying with just a partial value match. Values for "id" look like this: "123-abc" so now a query with just "abc" will match when querying against the "id" field. This is not how it worked previously (the keyword only field would require the entire value "123-abc").
Ideally, the top-level "id" field would be keyword only, and if a "full text" search was required, the query would need to specify "id.txt". So my question is... is there a way to disable multi-fields and require that the query explicitly set a sub field when needed?
My only other thought on how to solve this, was to use copy_to so that these fields are completely distinct... but that is a bit more work and there are many many fields to deal with that would require this.
Is there a way in ElasticSearch wherein I can remove some the objects in the nested field array.
So I have a nested field and it returns array of objects. I need to remove some objects in the nested field.
Is it possible to do so in the query or I need to do that in my code
These extra nested documents are hidden; we can’t access them directly. To update, add, or remove a nested object, we have to reindex the whole document. It’s important to note that, the result returned by a search request is not the nested object alone; it is the whole document.
Nested Objects Elastic search
As far as I know, In Elasticsearch you can't just remove part of a existing document. You should change the document (remove objects you don't need) and renew(rewrite) the document.
I have an elasticsearch (version 1.7) cluster with multiple indices. Each index has multiple doc_types, and each has fields w/ a variety of types. I'd like to get a list of field names for a given field type. This would be a necessarily nested list. For example, I'd like to query for field type "string", and return {index1: {doc_type1.1: [field1.1.1, field1.1.2], ...} -- the leaves of this nested dicts are only those fields w/ the given type. So the hits for this query won't be documents but rather a subset of the cluster's mapping. Is this possible using Elasticsearch?
One solution: I know I can get the mapping as a dict using Python, then work on the mapping dict to recover this nested list. But I think there should be an elasticsearch way of doing this, not a Python solution. In my searches through the documentation I just keep finding the "type filter" which filters by doc_type, not field type.
There's currently no way of achieving this. The _mapping endpoint will return all fields of the request mapping type(s).
However, there might be a way, provided your fields have a special naming convention hinting at their type, for instance name_str (string field for "name"), age_int (integer field for "age"), etc. In this case, you could use response filtering on the _mapping call and retrieve only the fields ending with _str:
curl -XGET localhost:9200/yourindex/_mapping/yourtype?filter_path=*_str
In Elasticsearch, is there any way to exclude the nested objects that don't match a particular query/filter from the resulting _source?
For example, let's say that a document has four objects in a nested field. Querying on the required filters results in only matching objects 1 and 3. When we get the results via _source, we will pull back the entire document along with objects 1,2,3,4.
Is it possible to exclude objects 2 and 4 from the results? Or is that something that we have to re-iterate and exclude using application-side logic?
At the moment there is no way to include only the matched nested objects in the result.
There is a inner_hits feature coming out in elasticsearch 1.5.0 which should help with this.
You can achieve this with use of inner_hits which will return you only matching nested objects. you can exclude this nested field in source.
Suggested by Val at:
ElasticSearch - Get only matching nested objects with All Top level fields in search response
I have a document whose structure changes often, how can I index nested documents inside it without changing the mapping on ElasticSearch?
You can index documents in Elasticsearch without providing a mapping yes.
However, Elasticsearch makes a decision about the type of a field when the first document contains a value for that field. If you add document 1 and it has a field called item_code, and in document 1 item_code is a string, Elasticsearch will set the type of field "item_code" to be string. If document 2 has an integer value in item_code Elasticsearch will have already set the type as string.
Basically, field type is index dependant, not document dependant.
This is mainly because of Apache Lucene and the way it handles this information.
If you're having a case where some data structure changes, while other doesn't, you could use an object type, http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/mapping-object-type.html.
You can even go as far as to use "enabled": false on it, which makes elasticsearch just store the data. You couldn't search it anymore, but maybe you actually don't even want that?