How to index multi dimension array in solr field - solr

Question

I am indexing Mysql database with solr, I have one-many relation between users table and order table:one user can have many orders.
order table have many columns (id, orderDate, caseNumber).
My goal is to index these tables in solr and have USR_ID field to store the user id, ORDERS feild type= multidimensional array to store each order for that user as an associative array.
the desired result is:
{
"USR_ID":"10",
"ORDERS":[
{"ID":"1" ,"ORDER_DATE":"12-03-2018", "CASE_NUMBER":"554"}, //FIRST FIELD
{"ID":"9","ORDER_DATE":"15-03-2018", "CASE_NUMBER":"569"} //SECOND FIELD
]
}
what i am getting is one dimensional array with all orders columns
{
"USR_ID":"10",
"ORDERS":[
"1", "12-03-2018", "554", //FIRST FIELD
"9", "15-03-2018", "569" //SECOND FIELD
]
}
Here is what I tried.
entities config in data-config.xml
<dataConfig>
<dataSource type="JdbcDataSource"
driver="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/mydb1"
user=""
password=""/>
<document>
<entity name="USERS"
pk="USR_ID"
query="SELECT USR_UID, FROM USERS"
deltaImportQuery="SELECT USR_UID, FROM USERS WHERE USR_UID='${dih.delta.USR_UID}'"
deltaQuery="SELECT USR_UID FROM USERS WHERE USERS.USR_UPDATE_DATE > '${dih.last_index_time}'">
<entity name="ORDER" pk="ID"
query="SELECT ID AS ORDERID, ORDER_DATE, CASE_NUMBER FROM ORDER WHERE USR_ID = '${USERS.USR_UID}'"
deltaQuery="select ID from ORDER where UPDATED_AT > '${dih.last_index_time}'"
parentDeltaQuery="SELECT USR_UID FROM USERS WHERE USR_UID = ${ORDER.USR_UID}">
<field column="ORDERID" name="ORDERS" />
<field column="CREATION_DATE" name="ORDERS" />
<field column="CASE_NUMBER" name="ORDERS" />
</entity>
</entity>
</document>
</dataConfig>
Here is fields definition in schema.xml file
<field name="USR_ID" type="string" indexed="true" stored="true" required="true" multiValued="false" />
<field name="ORDERS" type="text_general" indexed="true" stored="true" required="false" multiValued="true"/>

Answer 1

You will have to go with sub-documents, or at least have one document by order since you only have an Id at the root level :
{
"USR_ID":"10",
"ID":"1" ,
"ORDER_DATE":"12-03-2018",
"CASE_NUMBER":"554"
}
See this good explantion of nested documents :
http://yonik.com/solr-nested-objects/

Answer 2

The answer was to use the following attribute in child="true" field when u define your data-config.xml file
in my case
<entity child="true" name="ORDER" pk="ID"
query="SELECT ID AS ORDERID, ORDER_DATE, CASE_NUMBER FROM ORDER WHERE USR_ID = '${USERS.USR_UID}'"
deltaQuery="select ID from ORDER where UPDATED_AT > '${dih.last_index_time}'"
parentDeltaQuery="SELECT USR_UID FROM USERS WHERE USR_UID = ${ORDER.USR_UID}">
<field column="ORDERID" name="ORDERS" />
<field column="CREATION_DATE" name="ORDERS" />
<field column="CASE_NUMBER" name="ORDERS" />
</entity>