# Could someone help me ? --How to implement join datatype by Java API
**URL:** https://discuss.elastic.co/t/could-someone-help-me-how-to-implement-join-datatype-by-java-api/148781
**Category:** Elasticsearch
**Created:** [September 17, 2018, 7:39am UTC](https://discuss.elastic.co/t/could-someone-help-me-how-to-implement-join-datatype-by-java-api/148781 "2018-09-17T07:39:43Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Tina](https://discuss.elastic.co/u/Tina)
#### Post date: [September 17, 2018, 7:39am UTC](https://discuss.elastic.co/t/could-someone-help-me-how-to-implement-join-datatype-by-java-api/148781/1 "2018-09-17T07:39:43Z")
As the mapping type will be removed, so we plan to use the join datatype for parent/child doc, but I don't know which Java api should be used, could someone help provide below function by Java code ? thank you in advance.
```auto
PUT my_index { "mappings": { "_doc": { "properties": { "my_join_field": { "type": "join", "relations": { "question": "answer" } } } } } }
PUT my_index/_doc/1?refresh { "text": "This is a question", "my_join_field": { "name": "question" } }
PUT my_index/_doc/3?routing=1&refresh { "text": "This is an answer", "my_join_field": { "name": "answer", "parent": "1" } }
```
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [October 15, 2018, 7:39am UTC](https://discuss.elastic.co/t/could-someone-help-me-how-to-implement-join-datatype-by-java-api/148781/2 "2018-10-15T07:39:44Z")
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