Handling multiple search fields in cypher or py2neo - neo4j

Just getting started with cypher. Trying to understand best way to handle this case. I need to query database based on several search fields(not always present). Wondering what's the best way to handle it. For e.g I collect data from html post request
storeName = request.form['storeName']
storeCountry = request.form['storeCountry']
storeState = request.form['storeState']
storeCity = request.form['storeState']
I'm using flask framework, so defined this function with py2neo to handle search fields. Not sure if I got it right but if all fields are set correctly, hopefully, something like this should work fine
def get_search_results(skipNumber,limitNumber, storeName, storeCountry,storeState, storeCity):
query = """
MATCH (store:store) WHERE store.name = {storeName}
MATCH (store:store)-[:IS_IN_COUNTRY]->(c:Country) WHERE c.name = {storeCountry}
MATCH (store:store)-[:IS_IN_STATE]->(s:State) WHERE s.name = {storeState}
MATCH (store:store)-[:IS_IN_CITY]->(ct:City) WHERE ct.name = {storeCity}
RETURN user SKIP {skip} LIMIT {limit}
"""
return graph.cypher.execute(query, skip=skipNumber, limit=limitNumber, storeName=storeName, storeCountry=storeCountry, storeState=storeState, storeCity=storeCity)
I would like to handle cases where users only submit one or two fields.
For e.g
1. if users only submit store name, then I should be able to return all the nodes with that store name.
2. If users only submit store name and country. Return all the stores nodes in that country
3. If users only submit store name, country and state. Return all the stores nodes in that country and state
Is it possible to write a generic cypher query to handle such scenarios i.e ignore cases where field is not set or is None or I need to write different queries to handle each case ?

Related

here'ActiveRecord - Optional matching

If I have a Case model, which has multiple relations, how can I create a query that matches one or more relation.
Example: Case has Company which has a name. Case also has many Sessions which have a response. I want to create a query where I can search for one or more of those matching (Company name AND/OR Session response). If there's no company, but a Session response matches, it should return and visa versa.
What would be the best way to achieve this?
You can do the following:
sql_cond = 'companies.id IS NOT NULL OR sessions.id IS NOT NULL')
Case.includes(:company, :sessions).references(:company, :session).where(sql_cond)
It will return the Case records having at least 1 Company OR Session record associated.

Returning like count and whether current user liked a post in Cypher

I have a possibly bone-headed question, but I'm just starting out with Neo4j, and I hope someone can help me out with learning Cypher syntax, which I've just started learning and evaluating.
I have two User nodes, and a single NewsPost node. Both users LIKE the NewsPost. I'm able to construct a Cypher query to count the likes for the post, but I'm wondering if it's also possible to check if the current user has liked the post in the same query.
What I have so far for a Cypher query is
match (p:NewsPost)<-[r:LIKES]-(u:User)
where id(p) = 1
return p, count(*)
Which returns the post and like count, but I can't figure out the other part of "has the current user liked this post". I know you're not supposed to filter on <id>, but I learned that after the fact and I'll go back and fix it later.
So first, is it possible to answer the "has the current user liked this post" question in the same query? And if so, how do I modify my query to do that?
The smallest change to your query that adds a true/false test for a particular user liking the news post would be
MATCH (p:NewsPost)<-[r:LIKES]-(u:User)
WHERE ID(p) = 1
RETURN p, count(r), 0 < size(p<-[:LIKES]-(:User {email:"michael#nero.com"}))
This returns, in addition to your query, the comparison of 0 being less than the size of the path from the news post node via an incoming likes relationship to a user node with email address michael#nero.com. If there is no such path you get false, if there is one or more such paths you get true.
If that does what you want you can go ahead and change the query a little, for instance use RETURN ... AS ... to get nicer result identifiers, and so on.
What you are looking for is Case.
In your database you should have something unique for each user (id property, email or maybe login, I don't know), so you have to match this user, and then match the relation to the post you want, using case you can return a boolean.
Example:
Optional Match (u:User{login:"Michael"})-[r:LIKES]-(p:newPost{id:1})
return CASE WHEN r IS NULL THEN false ELSE true END as userLikesTopic
If you want to get the relation directly (to get a property in it as example) you can remove the CASE part and directly return r, if it does not exist, null will be returned from the query.

how to get solr results in given order specified in query

I have framed query to submit to solr which is of following format.
id:95154 OR id:68209 OR id:89482 OR id:94233 OR id:112481 OR id:93843
i want to get records according to order from starting. say i need to get document with id 95154 document first then id 68209 next and so on. but its not happening right now its giving last id 93843 first and some times random.i am using solr in grails 2.1 and my solr version is 1.4.0. here is sample way i am getting documents from solr
def server = solrService.getServer('provider')
SolrQuery sponsorSolrQuery = new SolrQuery(solarQuery)
def queryResponse = server.query(sponsorSolrQuery);
documentsList = queryResponse.getResults()
As #injecteer mentions, there is nothing built-in to Lucene to consider the sequence of clauses in a boolean query, but:
You are able to apply boosts to each term, and as long as the field is a basic field (meaning, not a TextField), the boosts will apply cleanly to give you a decent sort by score.
id:95154^6 OR id:68209^5 OR id:89482^4 OR id:94233^3 OR id:112481^2 OR id:93843
there's no such thing in Lucene (I strongly assume, that in Solr as well). In Lucene you can sort the results based on contents of documents' fields, but not on the order of clauses in a query.
that means, that you have to sort the results yourself:
documentsList = queryResponse.getResults()
def sordedByIdOrder = solarQueryAsList.collect{ id -> documentList.find{ it.id == id } }

Can Neo4j be effectively used to show a collection of nodes in a sortable and filterable table?

I realise this may not be ideal usage, but apart from all the graphy goodness of Neo4j, I'd like to show a collection of nodes, say, People, in a tabular format that has indexed properties for sorting and filtering
I'm guessing the Type of a node can be stored as a Link, say Bob -> type -> Person, which would allow us to retrieve all People
Are the following possible to do efficiently (indexed?) and in a scalable manner?
Retrieve all People nodes and display all of their names, ages, cities of birth, etc (NOTE: some of this data will be properties, some Links to other nodes (which could be denormalised as properties for table display's and simplicity's sake)
Show me all People sorted by Age
Show me all People with Age < 30
Also a quick how to do the above (or a link to some place in the docs describing how) would be lovely
Thanks very much!
Oh and if the above isn't a good idea, please suggest a storage solution which allows both graph-like retrieval and relational-like retrieval
if you want to operate on these person nodes, you can put them into an index (default is Lucene) and then retrieve and sort the nodes using Lucene (see for instance How do I sort Lucene results by field value using a HitCollector? on how to do a custom sort in java). This will get you for instance People sorted by Age etc. The code in Neo4j could look like
Transaction tx = neo4j.beginTx();
idxManager = neo4j.index()
personIndex = idxManager.forNodes('persons')
personIndex.add(meNode,'name',meNode.getProperty('name'))
personIndex.add(youNode,'name',youNode.getProperty('name'))
tx.success()
tx.finish()
'*** Prepare a custom Lucene query context with Neo4j API ***'
query = new QueryContext( 'name:*' ).sort( new Sort(new SortField( 'name',SortField.STRING, true ) ) )
results = personIndex.query( query )
For combining index lookups and graph traversals, Cypher is a good choice, e.g.
START people = node:people_index(name="E*") MATCH people-[r]->() return people.name, r.age order by r.age asc
in order to return data on both the node and the relationships.
Sure, that's easily possible with the Neo4j query language Cypher.
For example:
start cat=node:Types(name='Person')
match cat<-[:IS_A]-person-[born:BORN]->city
where person.age > 30
return person.name, person.age, born.date, city.name
order by person.age asc
limit 10
You can experiment with it in our cypher console.

Combining table, web service data in Grails

I'm trying to figure out the best approach to display combined tables based on matching logic and input search criteria.
Here is the situation:
We have a table of customers stored locally. The fields of interest are ssn, first name, last name and date of birth.
We also have a web service which provides the same information. Some of the customers from the web service are the same as the local file, some different.
SSN is not required in either.
I need to combine this data to be viewed on a Grails display.
The criteria for combination are 1) match on SSN. 2) For any remaining records, exact match on first name, last name and date of birth.
There's no need at this point for soundex or approximate logic.
It looks like what I should do is extract all the records from both inputs into a single collection, somehow making it a set on SSN. Then remove the blank ssn.
This will handle the SSN matching (once I figure out how to make that a set).
Then, I need to go back to the original two input sources (cached in a collection to prevent a re-read) and remove any records that exist in the SSN set derived previously.
Then, create another set based on first name, last name and date of birth - again if I can figure out how to make a set.
Then combine the two derived collections into a single collection. The collection should be sorted for display purposes.
Does this make sense? I think the search criteria will limit the number of record pulled in so I can do this in memory.
Essentially, I'm looking for some ideas on how the Grails code would look for achieving the above logic (assuming this is a good approach). The local customer table is a domain object, while what I'm getting from the WS is an array list of objects.
Also, I'm not entirely clear on how the maxresults, firstResult, and order used for the display would be affected. I think I need to read in all the records which match the search criteria first, do the combining, and display from the derived collection.
The traditional Java way of doing this would be to copy both the local and remote objects into TreeSet containers with a custom comparator, first for SSN, second for name/birthdate.
This might look something like:
def localCustomers = Customer.list()
def remoteCustomers = RemoteService.get()
TreeSet ssnFilter = new TreeSet(new ClosureComparator({c1, c2 -> c1.ssn <=> c2.ssn}))
ssnFilter.addAll(localCustomers)
ssnFilter.addAll(remoteCustomers)
TreeSet nameDobFilter = new TreeSet(new ClosureComparator({c1, c2 -> c1.firstName + c1.lastName + c1.dob <=> c2.firstName + c2.lastName + c2.dob}))
nameDobFilter.addAll(ssnFilter)
def filteredCustomers = nameDobFilter as List
At this point, filteredCustomers has all the records, except those that are duplicates by your two criteria.
Another approach is to filter the lists by sorting and doing a foldr operation, combining adjacent elements if they match. This way, you have an opportunity to combine the data from both sources.
For example:
def combineByNameAndDob(customers) {
customers.sort() {
c1, c2 -> (c1.firstName + c1.lastName + c1.dob) <=>
(c2.firstName + c2.lastName + c2.dob)
}.inject([]) { cs, c ->
if (cs && c.equalsByNameAndDob(cs[-1])) {
cs[-1].combine(c) //combine the attributes of both records
cs
} else {
cs << c
}
}
}

Resources