From the docs:
You can also chain multiple where() methods to create more specific queries (logical AND).
How can I perform an OR query?
Example:
Give me all documents where the field status is open OR upcoming
Give me all documents where the field status == open OR createdAt <= <somedatetime>
OR isn't supported as it's hard for the server to scale it (requires keeping state to dedup). The work around is to issue 2 queries, one for each condition, and dedup on the client.
Edit (Nov 2019):
Cloud Firestore now supports IN queries which are a limited type of OR query.
For the example above you could do:
// Get all documents in 'foo' where status is open or upcmoming
db.collection('foo').where('status','in',['open','upcoming']).get()
However it's still not possible to do a general OR condition involving multiple fields.
With the recent addition of IN queries, Firestore supports "up to 10 equality clauses on the same field with a logical OR"
A possible solution to (1) would be:
documents.where('status', 'in', ['open', 'upcoming']);
See Firebase Guides: Query Operators | in and array-contains-any
suggest to give value for status as well.
ex.
{ name: "a", statusValue = 10, status = 'open' }
{ name: "b", statusValue = 20, status = 'upcoming'}
{ name: "c", statusValue = 30, status = 'close'}
you can query by ref.where('statusValue', '<=', 20) then both 'a' and 'b' will found.
this can save your query cost and performance.
btw, it is not fix all case.
I would have no "status" field, but status related fields, updating them to true or false based on request, like
{ name: "a", status_open: true, status_upcoming: false, status_closed: false}
However, check Firebase Cloud Functions. You could have a function listening status changes, updating status related properties like
{ name: "a", status: "open", status_open: true, status_upcoming: false, status_closed: false}
one or the other, your query could be just
...where('status_open','==',true)...
Hope it helps.
This doesn't solve all cases, but for "enum" fields, you can emulate an "OR" query by making a separate boolean field for each enum-value, then adding a where("enum_<value>", "==", false) for every value that isn't part of the "OR" clause you want.
For example, consider your first desired query:
Give me all documents where the field status is open OR upcoming
You can accomplish this by splitting the status: string field into multiple boolean fields, one for each enum-value:
status_open: bool
status_upcoming: bool
status_suspended: bool
status_closed: bool
To perform your "where status is open or upcoming" query, you then do this:
where("status_suspended", "==", false).where("status_closed", "==", false)
How does this work? Well, because it's an enum, you know one of the values must have true assigned. So if you can determine that all of the other values don't match for a given entry, then by deduction it must match one of the values you originally were looking for.
See also
in/not-in/array-contains-in: https://firebase.google.com/docs/firestore/query-data/queries#in_and_array-contains-any
!=: https://firebase.googleblog.com/2020/09/cloud-firestore-not-equal-queries.html
I don't like everyone saying it's not possible.
it is if you create another "hacky" field in the model to build a composite...
for instance, create an array for each document that has all logical or elements
then query for .where("field", arrayContains: [...]
you can bind two Observables using the rxjs merge operator.
Here you have an example.
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/merge';
...
getCombinatedStatus(): Observable<any> {
return Observable.merge(this.db.collection('foo', ref => ref.where('status','==','open')).valueChanges(),
this.db.collection('foo', ref => ref.where('status','==','upcoming')).valueChanges());
}
Then you can subscribe to the new Observable updates using the above method:
getCombinatedStatus.subscribe(results => console.log(results);
I hope this can help you, greetings from Chile!!
We have the same problem just now, luckily the only possible values for ours are A,B,C,D (4) so we have to query for things like A||B, A||C, A||B||C, D, etc
As of like a few months ago firebase supports a new query array-contains so what we do is make an array and we pre-process the OR values to the array
if (a) {
array addObject:#"a"
}
if (b) {
array addObject:#"b"
}
if (a||b) {
array addObject:#"a||b"
}
etc
And we do this for all 4! values or however many combos there are.
THEN we can simply check the query [document arrayContains:#"a||c"] or whatever type of condition we need.
So if something only qualified for conditional A of our 4 conditionals (A,B,C,D) then its array would contain the following literal strings: #["A", "A||B", "A||C", "A||D", "A||B||C", "A||B||D", "A||C||D", "A||B||C||D"]
Then for any of those OR combinations we can just search array-contains on whatever we may want (e.g. "A||C")
Note: This is only a reasonable approach if you have a few number of possible values to compare OR with.
More info on Array-contains here, since it's newish to firebase docs
If you have a limited number of fields, definitely create new fields with true and false like in the example above. However, if you don't know what the fields are until runtime, you have to just combine queries.
Here is a tags OR example...
// the ids of students in class
const students = [studentID1, studentID2,...];
// get all docs where student.studentID1 = true
const results = this.afs.collection('classes',
ref => ref.where(`students.${students[0]}`, '==', true)
).valueChanges({ idField: 'id' }).pipe(
switchMap((r: any) => {
// get all docs where student.studentID2...studentIDX = true
const docs = students.slice(1).map(
(student: any) => this.afs.collection('classes',
ref => ref.where(`students.${student}`, '==', true)
).valueChanges({ idField: 'id' })
);
return combineLatest(docs).pipe(
// combine results by reducing array
map((a: any[]) => {
const g: [] = a.reduce(
(acc: any[], cur: any) => acc.concat(cur)
).concat(r);
// filter out duplicates by 'id' field
return g.filter(
(b: any, n: number, a: any[]) => a.findIndex(
(v: any) => v.id === b.id) === n
);
}),
);
})
);
Unfortunately there is no other way to combine more than 10 items (use array-contains-any if < 10 items).
There is also no other way to avoid duplicate reads, as you don't know the ID fields that will be matched by the search. Luckily, Firebase has good caching.
For those of you that like promises...
const p = await results.pipe(take(1)).toPromise();
For more info on this, see this article I wrote.
J
OR isn't supported
But if you need that you can do It in your code
Ex : if i want query products where (Size Equal Xl OR XXL : AND Gender is Male)
productsCollectionRef
//1* first get query where can firestore handle it
.whereEqualTo("gender", "Male")
.addSnapshotListener((queryDocumentSnapshots, e) -> {
if (queryDocumentSnapshots == null)
return;
List<Product> productList = new ArrayList<>();
for (DocumentSnapshot snapshot : queryDocumentSnapshots.getDocuments()) {
Product product = snapshot.toObject(Product.class);
//2* then check your query OR Condition because firestore just support AND Condition
if (product.getSize().equals("XL") || product.getSize().equals("XXL"))
productList.add(product);
}
liveData.setValue(productList);
});
For Flutter dart language use this:
db.collection("projects").where("status", whereIn: ["public", "unlisted", "secret"]);
actually I found #Dan McGrath answer working here is a rewriting of his answer:
private void query() {
FirebaseFirestore db = FirebaseFirestore.getInstance();
db.collection("STATUS")
.whereIn("status", Arrays.asList("open", "upcoming")) // you can add up to 10 different values like : Arrays.asList("open", "upcoming", "Pending", "In Progress", ...)
.addSnapshotListener(new EventListener<QuerySnapshot>() {
#Override
public void onEvent(#Nullable QuerySnapshot queryDocumentSnapshots, #Nullable FirebaseFirestoreException e) {
for (DocumentSnapshot documentSnapshot : queryDocumentSnapshots) {
// I assume you have a model class called MyStatus
MyStatus status= documentSnapshot.toObject(MyStatus.class);
if (status!= null) {
//do somthing...!
}
}
}
});
}
I tried many things but of no use.
I have already raised a question on stackoverflow earlier but I am still facing the same issue.
Here is the link to old stackoverflow question
creating multiple nodes with properties in json in neo4j
Let me try out explaining with a small example
This is the query I want to execute
{
"params" : {
"props" : [
{
"LocalAsNumber" : 0,
"NodeDescription" : "10TiMOS-B-4.0.R2 ",
"NodeId" : "10.227.28.95",
"NodeName" : "BLR_WAO_SARF7"
}
]
},
"query" : "MATCH (n:Router) where n.NodeId = {props}.NodeId RETURN n"}
For simplicity I have added only 1 props array otherwise there are around 5000 props. Now I want to execute the query above but it fails.
I tried using (props.NodeId}, {props[NodeID]} but everything fails.
Is it possbile to access a individual property in neo4j?
My prog is in c++ and I am using jsoncpp and curl to fire my queries.
If you do {props}.nodeId in the query then the props parameter must be a map, but you pass in an array. Do
"props" : {
"LocalAsNumber" : 0,
"NodeDescription" : "10TiMOS-B-4.0.R2 ",
"NodeId" : "10.227.28.95",
"NodeName" : "BLR_WAO_SARF7"
}
You can use an array of maps for parameter either with a simple CREATE statement.
CREATE ({props})
or if you loop through the array to access the individual maps
FOREACH (prop IN {props} |
MERGE (i:Interface {nodeId:prop.nodeId})
ON CREATE SET i = prop
)
Does this query string work for you?
"MATCH (n:Router) RETURN [p IN {props} WHERE n.NodeId = p.NodeId | n];"
Below is the code in question. I receive Object reference not set to an instance of an object. on the where clause inside the Linq query. However, this only happens after it goes through and builds my viewpage.
Meaning: If I step through using debugger, I can watch it pull the correct order I am filtering for, go to the correct ViewPage, fill in the model/table with the correct filtered item, and THEN it comes back to my Controller and shows me the error.
public ActionResult OrderIndex(string searchBy, string search)
{
var orders = repositoryOrder.GetOpenOrderList();
if (Request.QueryString["FilterOrderNumber"] != null)
{
var ordersFiltered = from n in orders
where n.OrderNumber.ToUpper().Contains(Request.QueryString["FilterOrderNumber"].ToUpper().ToString())
select n;
return View(ordersFiltered);
}
return View(orders);
}
its always better to manipulate your strings and other things outside the linq query ,
please refer : http://msdn.microsoft.com/en-us/library/bb738550.aspx
from the readability point of view also its not good ,
public ActionResult OrderIndex(string searchBy, string search)
{
var orders = repositoryOrder.GetOpenOrderList();
var orderNumber = Request.QueryString["FilterOrderNumber"];
if (!string.IsNullOrEmpty(orderNumber))
{
orderNumber = orderNumber.ToUpper();
var ordersFiltered = from n in orders
where n.OrderNumber.ToUpper().Contains(orderNumber)
select n;
return View(ordersFiltered);
}
return View(orders);
}
Your query is not being executed in your Action method because you don't have a ToList (or equivalent) added to your query. When your code returns, your query will be enumerated somewhere in your view and that's the point where the error occurs.
Try adding ToList to your query like this to force query execution in your action method:
var ordersFiltered = (from n in orders
where n.OrderNumber.ToUpper().Contains(Request.QueryString["FilterOrderNumber"].ToUpper().ToString())
select n).ToList();
What's going wrong is that a part of your where clause is null. This could be your query string parameter. Try moving the Request.QueryString part out of your query and into a temporary variable. If that's not the case make sure that your orders have an OrderNumber.
You both were right. Just separately.
This fixed my problem
var ordersFiltered = (from n in orders
where !string.IsNullOrEmpty(n.OrderNumber) && n.OrderNumber.ToUpper().Contains(Request.QueryString["FilterOrderNumber"].ToUpper().ToString())
select n);
Trying to execute the following cypher query (which executes ok from neoclipse)
START a=node(*) MATCH a-[:Knows]->p WHERE (p.Firstname! = "Steve" ) RETURN p
from neo4jclient with the following statement
protected void Populate()
{
var client = new GraphClient(new Uri("http://altdev:7474/db/data"));
client.Connect();
var query = client.Cypher
.Start(new RawCypherStartBit("all", "node(*)"))
.Match("all-[:Knows]->p")
.Where((Person p) => p.Firstname == "Steve")
.Return<Node<Person>>("Person");
var people = query.Results;
}
the client throws an exception, as follows
The query was: START all=node(*)
MATCH all-[:Knows]->p
WHERE (p.Firstname! = {p0})
RETURN Person
The response status was: 400 Bad Request
The response from Neo4j (which might include useful detail!) was: {
"message" : "Unknown identifier `Person`.",
"exception" : "SyntaxException",
"fullname" : "org.neo4j.cypher.SyntaxException",
"stacktrace" : [ "org.neo4j.cypher.internal.symbols.SymbolTable.evaluateType(SymbolTable.scala:59)", "org.neo4j.cypher.internal.commands.expressions.Identifier.evaluateType(Identifier.scala:47)", "org.neo4j.cypher.internal.commands.expressions.Expression.throwIfSymbolsMissing(Expression.scala:52)", "org.neo4j.cypher.internal.pipes.ColumnFilterPipe$$anonfun$throwIfSymbolsMissing$1.apply(ColumnFilterPipe.scala:61)", "org.neo4j.cypher.internal.pipes.ColumnFilterPipe$$anonfun$throwIfSymbolsMissing$1.apply(ColumnFilterPipe.scala:61)", "scala.collection.immutable.List.foreach(List.scala:309)", "org.neo4j.cypher.internal.pipes.ColumnFilterPipe.throwIfSymbolsMissing(ColumnFilterPipe.scala:61)", "org.neo4j.cypher.internal.pipes.PipeWithSource.<init>(Pipe.scala:63)", "org.neo4j.cypher.internal.pipes.ColumnFilterPipe.<init>(ColumnFilterPipe.scala:30)", "org.neo4j.cypher.internal.executionplan.builders.ColumnFilterBuilder.handleReturnClause(ColumnFilterBuilder.scala:60)", "org.neo4j.cypher.internal.executionplan.builders.ColumnFilterBuilder.apply(ColumnFilterBuilder.scala:38)", "org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl.prepareExecutionPlan(ExecutionPlanImpl.scala:54)", "org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl.<init>(ExecutionPlanImpl.scala:36)", "org.neo4j.cypher.ExecutionEngine$$anonfun$prepare$1.apply(ExecutionEngine.scala:80)", "org.neo4j.cypher.ExecutionEngine$$anonfun$prepare$1.apply(ExecutionEngine.scala:80)", "org.neo4j.cypher.internal.LRUCache.getOrElseUpdate(LRUCache.scala:37)", "org.neo4j.cypher.ExecutionEngine.prepare(ExecutionEngine.scala:80)", "org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:72)", "org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:76)", "org.neo4j.cypher.javacompat.ExecutionEngine.execute(ExecutionEngine.java:79)", "org.neo4j.server.rest.web.CypherService.cypher(CypherService.java:94)", "java.lang.reflect.Method.invoke(Method.java:616)", "org.neo4j.server.rest.security.SecurityFilter.doFilter(SecurityFilter.java:112)" ]
}
As you can see, essentially the queries are the same. And the nodes I'm trying to get are of _type "Person"
TIA
Marcelo
In your MATCH clause you use the identity p:
.Match("all-[:Knows]->p") // becomes MATCH all-[:Knows]->p
In your RETURN clause you change to using the identity Person:
.Return<Node<Person>>("Person"); // becomes RETURN person
You need to pick one and be consistent.
Integrating some other clean up too, your full query should be:
var query = client.Cypher
.Start(new { all = All.Nodes })
.Match("all-[:Knows]->p")
.Where((Person p) => p.Firstname == "Steve")
.Return<Person>("p");
It's down to the way you are creating the Cypher code, specifically what you are returning:
var query = client.Cypher
.Start(new RawCypherStartBit("all", "node(*)"))
.Match("all-[:Knows]->p")
.Where((Person p) => p.Firstname == "Steve")
.Return<Node<Person>>("p"); // <-- THIS LINE SHOULD SAY 'P' NOT 'Person'
The return statement requires the name to be the same as the node you have defined. So you use: all-[:knows]->p where you define p. Now you need to return it.
(Which is what Peter is saying in his answer :))
You are trying to return a Person node that is not assigned to anything in the query.
I am trying to iterate over a list of parameters, in a grails controller. when I have a list, longer than one element, like this:
[D4L2DYJlSw, 8OXQWKDDvX]
the following code works fine:
def recipientId = params.email
recipientId.each { test->
System.print(test + "\n")
}
The output being:
A4L2DYJlSw
8OXQWKDDvX
But, if the list only has one item, the output is not the only item, but each letter in the list. for example, if my params list is :
A4L2DYJlSwD
using the same code as above, the output becomes:
A
4
L
2
D
Y
J
l
S
w
can anyone tell me what's going on and what I am doing wrong?
thanks
jason
I run at the same problem a while ago! My solution for that it was
def gameId = params.gameId
def selectedGameList = gameId.class.isArray() ? Game.getAll(gameId as List) : Game.get(gameId);
because in my case I was getting 1 or more game Ids as parameters!
What you can do is the same:
def recipientId = params.email
if(recipientId.class.isArray()){
// smtg
}else{
// smtg
}
Because what is happening here is, as soon as you call '.each' groovy transform that object in a list! and 'String AS LIST' in groovy means char_array of that string!
My guess would be (from what I've seen with groovy elsewhere) is that it is trying to figure out what the type for recipientId should be since you haven't given it one (and it's thus dynamic).
In your first example, groovy decided what got passed to the .each{} closure was a List<String>. The second example, as there is only one String, groovy decides the type should be String and .each{} knows how to iterate over a String too - it just converts it to a char[].
You could simply make recipientId a List<String> I think in this case.
You can also try like this:
def recipientId = params.email instanceof List ? params.email : [params.email]
recipientId.each { test-> System.print(test + "\n") }
It will handle both the cases ..
Grails provides a built-in way to guarantee that a specific parameter is a list, even when only one was submitted. This is actually the preferred way to get a list of items when the number of items may be 0, 1, or more:
def recipientId = params.list("email")
recipientId.each { test->
System.print(test + "\n")
}
The params object will wrap a single item as a list, or return the list if there is more than one.