Nested entities not imported / do not show up in search?

[Matthias Fischer]

Hello everybody,

I am trying to import from an Oracle DB 11g2 via DIH using SOLR 5.3.1. 
In my relational DB there are company addresses (table tb_firmen_adressen) and 
branches (table tb_branchen). They have an n:m relationship using the join 
table tb_firmen_branchen. 
Now I would like to find companies by their name and in each company result I 
would like to see the associated branches.
However I only get the companies without the nested entries. As a newbie I'd 
highly appreciate some help as there are no errors or warnings in the log file 
and I could not find any helpful hints in the documentation or elsewhere in the 
internet concerning my problem. 

Here is my data config:

    <dataConfig>
        <dataSource name="jdbc" driver="oracle.jdbc.driver.OracleDriver" 
url="jdbc:oracle:thin:@//xxxxx.xxxxxxx:1521/pde11" user="myuser" 
password="mysecret"/>
    <document>
        <entity name="firma" pk="fa.EBI_NR" query="
            SELECT fa.EBI_NR, fa.NAMENSZEILE_1, fa.NAMENSZEILE_2, 
fa.NAMENSZEILE_3
            FROM tb_firmen_adressen fa 
            WHERE rownum &lt; 10000
        ">
                                            
            <field name="firma_ebi_nr"                  column="EBI_NR" />
            <field name="firma_namenszeile_1"   column="NAMENSZEILE_1" />
            <field name="firma_namenszeile_2"   column="NAMENSZEILE_2" />
            <field name="firma_namenszeile_3"   column="NAMENSZEILE_3" />
                    
            <entity name="firma_branche" child="true" query="
                SELECT b.EBC_CODE AS EBC_CODE
                FROM 
                    tb_firmen_branchen fb 
                        JOIN tb_branchen b ON fb.EBC_CODE = b.EBC_CODE 
                WHERE fb.EBI_NR='${firma.firma_ebi_nr}'
            ">
                <field name="branche_ebc_code" column="EBC_CODE" />
                <!-- I would like to add more fields later here once I get it 
to work -->
            </entity>
      
        </entity>
    </document>
    </dataConfig>


And here are the relevant lines from my schema file:

    <uniqueKey>firma_ebi_nr</uniqueKey>

     <field name="firma_ebi_nr"                 type="long"             
required="true"         indexed="true"  stored="true"/>
     <field name="firma_namenszeile_1"  type="text_general"                     
        indexed="true"  stored="true"/>
     <field name="firma_namenszeile_2"  type="text_general"                     
        indexed="true"  stored="true"/>
     <field name="firma_namenszeile_3"  type="text_general"                     
        indexed="true"  stored="true"/>
     <field name="branche_ebc_code"             type="long"                     
                indexed="true"  stored="true"/>
     


After restarting solr and calling 
http://localhost:8983/solr/jcg/dataimport?command=full-import I get "Indexing 
completed. Added/Updated: 9999 documents. Deleted 0 documents."
So basically it seams to work, but my search results look like this:

{
  "responseHeader":{
    "status":0,
    "QTime":71,
    "params":{
      "q":"Der Bunte",
      "defType":"edismax",
      "indent":"true",
      "qf":"firma_namenszeile_1",
      "wt":"json"}},
  "response":{"numFound":85,"start":0,"docs":[
      {
        "firma_ebi_nr":123123123,
        "firma_namenszeile_1":"Der Bunte Laden",
        "_version_":1515185579421073408},
      {
     ...
}

Why are there no company branches inside the company records? What's wrong with 
my configuration? Any help is appreciated!

Kind regards
Matthias Fischer