Azure Cognitive Search: How to map embedded document column? - azure-cognitive-search

Question

I have mongodb as the backend datasource when creating the ACS index and some columns from mongodb is _id. Per definition of the ACS indexer the name can not start with _ so I will need to create some mapping for the mongodb collection columns to the ACS index names.
The mongodb data is like below:
"customer": {
"_id": {
"$oid": "623a4b1bdb6d0a1210fd0234"
},
"customerName": "Andrew Jr"
}
The ACS index definition I created is:
{
"name": "customer",
"type": "Edm.ComplexType",
"fields": [
{
"name": "id",
"type": "Edm.String",
"searchable": true,
"filterable": true,
"retrievable": true,
"sortable": true,
"facetable": true,
"key": false,
"indexAnalyzer": null,
"searchAnalyzer": null,
"analyzer": null,
"normalizer": null,
"synonymMaps": []
},
{
"name": "customerName",
"type": "Edm.String",
"searchable": true,
"filterable": true,
"retrievable": true,
"sortable": true,
"facetable": true,
"key": false,
"indexAnalyzer": null,
"searchAnalyzer": null,
"analyzer": null,
"normalizer": null,
"synonymMaps": []
}
]
}
So basically I want to map the field _id inside customer embedded document from the mongodb data source to the index column id.
I tried to use the indexer to map them together :
"fieldMappings": [ { "sourceFieldName" : "_id", "targetFieldName" : "id" } ],
I am getting the error: Field mapping specifies target field 'id' that doesn't exist in the index
How can I define the sourceFieldName and targertFieldName to reference to embedded document ?

Answer 1

Change the "targetFieldName" value to "name" instead of "id" and check with the execution.
"fieldMappings": [ { "sourceFieldName" : "_id", "targetFieldName" : "id" } ],

Answer 2

You can manage the field mappings of an existing indexer using the Update Indexer API request.
PUT https://[service name].search.windows.net/indexers/myindexer?api-version=[api-version]
Content-Type: application/json
api-key: [admin key]
{
"dataSourceName" : "mydatasource",
"targetIndexName" : "myindex",
"fieldMappings" : [ { "sourceFieldName" : "_id", "targetFieldName" : "id" } ]
A source field can be referenced in multiple field mappings.
"fieldMappings" : [
{ "sourceFieldName" : "text", "targetFieldName" : "textStandardEnglishAnalyzer" },
{ "sourceFieldName" : "text", "targetFieldName" : "textSoundexAnalyzer" }
]
}