etl and many to many relation - orientdb

Question

In documentation the etl from csv use one to many feature, I would like to extends it to many to many. So I made 3 configs, one for post, one for comment and one for relation. Post and Comment are ok but when I launch relation I have got this error, what I'm doing wrong ?
commentId,postId
0,10
1,10
21,10
41,20
82,20
{
"source": { "file": { "path": "/tmp/relation.csv" } },
"extractor": { "csv": {} },
"transformers": [
{ "edge":
{ "class": "HasComments", "joinFieldName": "postId", "lookup": "Post.id", "direction": "out"},
{ "class": "HasComments", "joinFieldName": "commentId", "lookup": "Comment.id", "direction": "in"}
}
],
"loader": {
"orientdb": {
"dbURL": "plocal:/tmp/test",
"dbType": "graph",
"classes": [
{"name": "Post", "extends": "V"},
{"name": "Comment", "extends": "V"},
{"name": "HasComments", "extends": "E"}
],
"indexes": [
{"class":"Post", "fields":["id:integer"], "type":"UNIQUE" },
{"class":"Comment", "fields":["id:integer"], "type":"UNIQUE" }
]
}
}
}
OrientDB etl v.2.1.9-SNAPSHOT (build 2.1.x#r; 2016-01-07 10:51:24+0000) www.orientdb.com
BEGIN ETL PROCESSOR
[file] INFO Reading from file /tmp/relation.csv with encoding UTF-8
Error in Pipeline execution: com.orientechnologies.orient.etl.transformer.OTransformException: edge: input type 'com.orientechnologies.orient.core.record.impl.ODocument$1$1#72ade7e3' is not supported
ETL process halted: com.orientechnologies.orient.etl.OETLProcessHaltedException: Halt
Exception in thread "main" com.orientechnologies.orient.etl.OETLProcessHaltedException: Halt
at com.orientechnologies.orient.etl.OETLPipeline.execute(OETLPipeline.java:149)
at com.orientechnologies.orient.etl.OETLProcessor.executeSequentially(OETLProcessor.java:448)
at com.orientechnologies.orient.etl.OETLProcessor.execute(OETLProcessor.java:255)
at com.orientechnologies.orient.etl.OETLProcessor.main(OETLProcessor.java:109)
Caused by: com.orientechnologies.orient.etl.transformer.OTransformException: edge: input type 'com.orientechnologies.orient.core.record.impl.ODocument$1$1#72ade7e3' is not supported
at com.orientechnologies.orient.etl.transformer.OEdgeTransformer.executeTransform(OEdgeTransformer.java:107)
at com.orientechnologies.orient.etl.transformer.OAbstractTransformer.transform(OAbstractTransformer.java:37)
at com.orientechnologies.orient.etl.OETLPipeline.execute(OETLPipeline.java:115)
... 3 more

Answer 1

One possible solution might be, after importing the Post and Comment classes through their json file, you can use another json file and import the class Relation
{
"source": { "file": { "path": "/tmp/relation.csv" } },
"extractor": { "row": {} },
"transformers": [
{ "csv": { "separator": ","}
},
{ "vertex": { "class": "Relation" } }
],
"loader": {
"orientdb": {
"dbURL": "plocal:/tmp/test",
"dbType": "graph",
"classes": [
{"name": "Post", "extends": "V"},
{"name": "Comment", "extends": "V"},
{"name": "Relation", "extends": "V"},
{"name": "HasComments", "extends": "E"}
],
"indexes": [
{"class":"Post", "fields":["id:integer"], "type":"UNIQUE" },
{"class":"Comment", "fields":["id:integer"], "type":"UNIQUE" }
]
}
}
}
You'll get these records.
Using the following javascript function
var g=orient.getGraphNoTx();
var relation = g.command("sql","select from Relation");
for(i=0;i<relation.length;i++){
var relationMM=g.command("sql","select postId , commentId from "+ relation[i].getId());
var idPost=relationMM[0].getProperty("postId");
var idComment=relationMM[0].getProperty("commentId");
var post=g.command("sql","select from Post where id = " + idPost);
var comment=g.command("sql","select from Comment where id = " + idComment);
g.command("sql","create edge HasComments from " + post[0].getId() + " to " + comment[0].getId());
}
g.command("sql","drop class Relation unsafe");
You'll get the following structure.
This will be your graph.
UPDATE
You can use this code to check if the edge already exists
var counter=g.command("sql","select count(*) from HasComments where out=" + post[0].getId() + " and in=" + comment[0].getId());
if(counter[0].getProperty("count")==0){
g.command("sql","create edge HasComments from " + post[0].getId() + " to " + comment[0].getId());
}