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Questions tagged [memgraphdb]

Use this tag for questions related to Memgraph streaming graph database.

Memgraph is an open source graph database built for real time streaming data, compatible with Neo4j. It is an in-memory graph database that uses Cypher as a query language. Memgraph can be extended with graph algorithms that are part of Memgraph Advanced Graph Extensions (MAGE). Graphs can be visualized using Memgraph Lab application.

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Memgraph - How to find the closest node with specific property efficiently

I have a pretty large network that contains privileged information. Because of this i can't share the exact graph but in its simplest form it can be abstracted as follows. (Person{name:str, age:int})-[:KNOWS]-(Person{name:str, age:int}) I would…
Jasper
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How to know if CREATE query failed in Memgraph through Neo4j Java driver?

Description I'm attempting to use Memgraph in my application by connecting to it using the Neo4j Java driver. I have a constraint that nodes of a certain label must have a certain property. When I try to create a node without that property, the…
shadowyfour
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Memgraph cypher recursive tree with depth and filtering query

I'm using Memgraph (but open to using Neo4j) and need some help on building a recursive query to build out a tree. I'm new to Cypher so my attempts so far haven't been successful. I've played around with the CALL subqueries but can't seem to get the…
NathanS
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In which form Memgraph supports graph projection?

As a part of the project, I need to project some subgraphs from the main graph. However, I'm unclear about the mechanisms Memgraph provides to support graph projection. I need to isolate a certain part of the graph. I've taken a look at similar…
GrandMel
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How can I import a simple json dataset into memgraph

I have read all information about importing json but find that documentation poor. The memgraph docs say, just do this: CALL json_util.load_from_url("https://download.memgraph.com/asset/mage/data.json") YIELD objects UNWIND objects AS o RETURN…
citykid
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How can I run mgbench without re-importing dataset?

I am running the mgbench multiple times. I notice that it needs to create database every time in a temp directory when I re-run a benchmark. If I have already a database in a data directory, how can I allocate my data directory to avoid importing…
jiamin hou
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Dijkstra's algorithm in Memgraph

I'm trying to run Dijkstra's algorithm in Memgraph on a dataset containing nodes with different properties, one of them being Euro and with different relationships, one of them being :MarriedTo. My goal is to find the weighted shortest path between…
MPesi
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Creating a Query Module in Memgraph

I'm using Memgraph Lab for a project related to music genres and I imported a dataset structured something like this: The dataset is composed of 2k users. Each user is defined by id and a list of genres he loves. The edges represent the mutual…
mattrixxxx
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Returning all nodes with and without relationships

In the neo4j browser MATCH (n) RETURN n shows all nodes with all relationships. How does one do this in memgraph lab? I can display the relevant nodes with relationships: MATCH links = (Projectlist)-[:references]-(Reflist) RETURN links this does…
Dewald
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How to check if a certain relationship goes both ways on Memgraph?

I have a dataset in Memgraph and I'm trying to check if a certain relationship goes both ways. But I'm either getting a failed query or wrong results.
An Martin
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Failed query in Memgraph

I am trying to execute the following query from Memgraph's documentation: MATCH (p:Person) WHERE exists((p)-[:LIVING_IN]->(:Country {name: 'Germany'})) RETURN p.name ORDER BY p.name; but I'm getting this error: Query failed: Not yet implemented:…
MPesi
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Can I run two instances of Memgraph and use data persistence at the same time?

I've found the question that explains that it is possible to run two Memgraph instances at the same time when you are using Docker. I've used the commands from that answer to run the instances: Fist instance: docker run -it -p 7687:7687 -p…
GrandMel
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Importing cpyherl files into Memgraph

I got a sample-data.cypherl file that looks like this: CREATE (:Factory {id: "200", name: "Factory Alpha", location: "New York"}); CREATE (:Warehouse {id: "201", name: "Warehouse Bravo", location: "Berlin"}); CREATE (:Retailer {id: "202", name:…
TenTonBonton
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Can reserved keyword be used as variable in Memgraph?

I'm starting to learn Cypher. I've read the openCypher specification, and I've spun up few different graph databases that use Cypher. At the moment I'm running Memgraph inside Docker. Here is my query that works just fine MATCH (p:Park) WITH…
TenTonBonton
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Does GQLAlchemy support migrations equivalent to DjangoORM or Alembic?

I'm learning how to do whings with GQLAlchemy. And I wonder does GQLAlchemy support migrations equivalent to DjangoORM or Alembic?
GrandMel
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