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Extract subgraph in neo4j using cypher query

I'm using neo4j 3.1 with java 8 and I want to extract a connected subgraph as to store it as a test database.
Is it possible to do it and how?
How to do it with the clause Return which returns the output. So, I had to create new nodes and relations or just export the subgraph and put it in a new database.
How can I extract a connected subgraph since I have a disconnected graph.
Thank you

There are two parts to this...getting the connected subgraph, and then finding a means to export.
APOC Procedures seems like it can cover both of these. The approach in this answer using the path expander should get you all the nodes in the connected subgraph (if the relationship type doesn't matter, leave off the relationshipFilter parameter).
The next step is to get all relationships between all of those nodes. APOC's apoc.algo.cover() function in the graph algorithms section should accomplish this.
Something like this (assuming this is after the subgraph query, and subgraphNode is in scope for the column of distinct subgraph nodes):
...
WITH COLLECT(subgraphNode) as subgraph, COLLECT(id(subgraphNode)) as ids
CALL apoc.algo.cover(ids) YIELD rel
WITH subgraph, COLLECT(rel) as rels
...
Now that you have the collections of both the nodes and relationships in the subgraph, you can export them.
APOC Procedures offers several means of exporting, from CSV to CypherScript. You should be able to find an option that works for you.

You can also use the neo4j-shell to extract the result of a query to a file and use this same file to re-import it in the neo4j database :
ikwattro#graphaware-team ~/d/_/310> ./bin/neo4j-shell -c 'dump MATCH (n:Product)-[r*2]->(x) RETURN n, r, x;' > result.cypher
check the file
ikwattro#graphaware-team ~/d/_/310> cat result.cypher
begin
commit
begin
create (_1:`Product` {`id`:"product123"})
create (_2:`ProductInformation` {`id`:"product123EXCEL"})
create (_3:`ProductInformationElement` {`id`:"product123EXCELtitle", `key`:"title", `value`:"Original Title"})
create (_5:`ProductInformationElement` {`id`:"product123EXCELproduct_type", `key`:"product_type", `value`:"casual_bag"})
create (_1)-[:`PRODUCT_INFORMATION`]->(_2)
create (_2)-[:`INFORMATION_ELEMENT`]->(_3)
create (_2)-[:`INFORMATION_ELEMENT`]->(_5)
;
commit
Use this file for feeding another neo4j :
ikwattro#graphaware-team ~/d/_/310> ./bin/neo4j-shell -file result.cypher
Transaction started
Transaction committed
Transaction started
+-------------------+
| No data returned. |
+-------------------+
Nodes created: 4
Relationships created: 3
Properties set: 8
Labels added: 4
52 ms
Transaction committed

How to force composite indexes to appear in Google Cloud?

Ok, see this picture in Google Cloud:
It said "Below are the composite indexes for this application. These indexes are managed in your app's index configuration file."
And see this following code:
public static long getPropertyMaxIDStronglyConsistent(String entityName, String propertyName, Key parentKey){
// Order alphabetically by property name:
//Key parentKey=KeyFactory.createKey(parentEntityName, parentName);
Query q = new Query(entityName, parentKey).setAncestor(parentKey)
.addSort(propertyName, SortDirection.DESCENDING);
//List<Entity> results = datastore.prepare(q).asList(FetchOptions.Builder.withDefaults());
List<Entity> results = datastore.prepare(q)
.asList(FetchOptions.Builder.withLimit(5));
if(results.size()>0){
Entity e=results.get(0);
long maxID=(Long)e.getProperty(propertyName);
return maxID;
}
else{
return 0;
}
}
Suppose that we are running this function1 getPropertyMaxIDStronglyConsistent("EnglishClass", "ClassNo", KeyFactory.createKey("EnglishClassParent", "EnglishClassParentName")).
What I found out that, the function1 is not gonna work if the kind "EnglishClass" does not appear in Indexes Table with "serving" status.
I didn't know what I did but after I was struggling for a few hours then suddenly the Index "EnglishClass" appeared. When the "EnglishClass" appeared with "serving" status, the app can work as normal without any problem.
My questions are
What are composite indexes?
Why didn't it appear immediately after running the function1?
What does "serving" status mean?
How to force composite indexes to appear in Google Cloud?
Extra:
In the datastore-indexes-auto.xml I have
<datastore-indexes autoGenerate="true">
<datastore-index kind="EnglishClass" ancestor="true" source="auto">
<property name="ClassNo" direction="desc"/>
</datastore-index>
</datastore-indexes>
But it still did not work

Indexes for the App Engine datastore are described in these docs and these docs(Java 7, but the principles are the same for Java 8).
A composite index is an index that comprises of more than one property of a model: for example an index that sorts a model by Model.name, then Model.creationDate. Composite indexes are used by queries that need to access datastore records in the order described by the query.
Some indexes must be declared in the datastore-indexes.xml file - see here
Serving status means that the index is ready for use; when an index is first uploaded App Engine must build the index, and until the index is built queries that use the building index will throw an exception. So it can be helpful to update indexes before deploying the code that requires them.
Configure your app to automatically configure indexes.

How do I query OrientDB Vertex graph object by Record ID in Java?

How do I retrieve an OrientDB Document/Object or Graph object using its Record ID? (Language: Java)
I'm referring to http://orientdb.com/docs/2.0/orientdb.wiki/Tutorial-Record-ID.html and Vertex.getId() / Edge.getId() methods.
It is just like an SQL query "SELECT * from aTable WHERE ID = 1".
Usage/purpose description: I want to store the generated ID after it is created by OrientDB, and later retrieve the same object using the same ID.

(1) I'd suggest using OrientDB 2.1, and its documentation, e.g. http://orientdb.com/docs/2.1/Tutorial-Record-ID.html
(2) From your post, it's unclear to me whether you need help obtaining the RID from the results of a query, or retrieving an object given its RID, so let me begin by mentioning that the former can be accomplished as illustrated by this example (in the case of an INSERT query):
ODocument result=db.command(new OCommandSQL(<INSERTQUERY>)).execute();
System.out.println(result.field("#rid"));
Going the other way around, there are several approaches. I have verified that the following does work using Version 2.1.8:
OrientGraph graph = new OrientGraph("plocal:PATH_TO_DB", "admin", "admin");
Vertex v = graph.getVertex("#16:0");
An alternative and more generic approach is to construct and execute a SELECT query of the form SELECT FROM :RID, along the lines of this example:
List<ODocument> results = db.query(new OSQLSynchQuery<ODocument>("select from " + rid));
for (ODocument aDoc : results) {
System.out.println(aDoc.field("name"));
}
(3) In practice, it will usually be better to use some other "handle" on OrientDB vertices and edges in Java code, or indeed when using any of the supported programming languages. For example, once one has a vertex as a Java Vertex, as in the "Vertex v" example above, one can usually use it.

How to pass neo4j Nodes from one database to another

I have two separate Database for Neo4j nodes. How can i pass Nodes from one database to another??
LIKE
1. Machine1 - GraphDB1- (Nodes-Students)
2.Machine2 - GraphDB2- (Nodes-Books)
so how can i pass book nodes to GraphDB1.
Any help would be appreciated.

You wouldn't do that, you would create all your data in one database.
In general you can query one databases with Cypher and then create / insert the data in the second database.
On the first database, return a node and relationship-list:
start n=node(*)
match n-[r]->()
return n,r
Us a programming language to create a CSV file or a set of cypher CREATE statements from those results. For importing CSV see: http://neo4j.org/develop/import esp. the "spreadsheet method" and/or the CSV batch-importer.
Enable auto-indexing in your second server: http://docs.neo4j.org/chunked/milestone/auto-indexing.html
Cypher Create statements for nodes and relationships look like this:
CREATE ({name:"Foo", age: 12});
CREATE ({name:"Bar", age: 18});
START n=node:node_auto_index(name="Foo"),
m=node:node_auto_index(name="Bar")
CREATE n-[:KNOWS {since:2012}]->m;
You can also check out my Neo4j-Import tools for the Neo4j-Shell: https://github.com/jexp/neo4j-shell-tools

Get the _id of the last upserted document in java

I need to find the _id of the last upserted document in java. I am using 2.0.5. I do not see an 'upserted' field in the output returned by getLastError if the element was updated. I do see it if the element was inserted. I need to get the _id regardless of whether the element was updated or inserted. Is it possible to get the _id of the document in some way other than issuing another find command? I am trying to reduce the unnecessary query.

You can use DBCollection.findAndModify(). You can set it's parameters such that it will perform the upsert and return a DBObject containing the _id of the object you just created/modified.
Check out the docs for a lot more info:
http://www.mongodb.org/display/DOCS/findAndModify+Command
ADDENDUM: I just revisited my answer and realize that there's a better, easier way. The value of _id is always set client-side, before the document is sent over the wire to the server. The driver does this for you, if you haven't assigned a value to the _id already. Since the client sets the _id, you know what it is even before the insert operation start. consider this example.
> var id = ObjectId()
> id
ObjectId("5511062d729ddce46b99ea3f")
> db.test.insert( { _id: id, text:"a trivial experiment"})
WriteResult({ "nInserted" : 1 })
> db.test.find( { _id: id} )
{
"_id" : ObjectId("5511062d729ddce46b99ea3f"),
"text" : "a trivial experiment"
}

Following Code Will Give You last Modified record:
db.products.find().sort({"$natural":1}).limit(1);
Following Codes Will Give You last Inserted record:
db.products.find().sort({"_id":-1}).limit(1);
db.products.find().sort({"$natural":-1}).limit(1);