neo4j

Neo4j CQL - （6）-关系基础

由 只谈情不闲聊 提交于 2019-12-23 13:50:03
Neo4j图数据库遵循属性图模型来存储和管理其数据。 根据属性图模型， 关系应该是定向的 。 否则，Neo4j将抛出一个错误消息。 基于方向性，Neo4j关系被分为 两种主要类型 。 单向关系 双向关系 在以下场景中，我们可以使用Neo4j CQL CREATE命令来创建两个节点之间的关系。 这些情况适用于Uni和双向关系。 在两个现有节点之间创建无属性的关系 在两个现有节点之间创建与属性的关系 在两个新节点之间创建无属性的关系 在两个新节点之间创建与属性的关系 在具有WHERE子句的两个退出节点之间创建/不使用属性的关系 我们将创建客户和CreditCard之间的关系，如下所示： 在上一章中，我们已经创建了Customer和CreditCard节点。 现在我们将看到如何创建它们之间的关系 此图描述了客户与CreditCard之间的关系 客户→信用卡 这里的关系是箭头标记（→） 由于Neo4j CQL语法是以人类可读的格式。 Neo4j CQL也使用类似的箭头标记来创建两个节点之间的关系。 每个关系（→）包含两个节点 从节点 到节点 从上图中，Customer节点是“From Node”，CreditCard Node是“To Node”这种关系。 对于节点，它们是两种关系 传出关系 传入关系 从上图中，关系是到 客户节点的“传出关系” ，并且相同的关系是到 信用卡节点的“传入关系

Neo4j https communication

由 杀马特。学长 韩版系。学妹 提交于 2019-12-23 12:53:57
问题 Is there any way to allow only https, instead of http, for the communication with the Neo4j server? Also, which channel does the Neo4j Shell's communication use, http or https? 回答1: This is from Neo4j Documentation: HTTPS support The Neo4j server includes built in support for SSL encrypted communication over HTTPS. The first time the server starts, it automatically generates a self-signed SSL certificate and a private key. Because the certificate is self signed, it is not safe to rely on for

How to update several vertex properties on Gremlin?

由 无人久伴 提交于 2019-12-23 12:32:04
问题 I want to add several properties on a vertex. I could do: g.v(1).firstname='Marko' g.v(1).lastname='Rodriguez' But how to add these properties with the following hash {firstname:'Marko', lastname:'Rodriguez'} in a single query? 回答1: You can construct a SideEffect pipe that would work. In the simple case, do this: g.v(1)._().sideEffect{it.firstname='Marko'; it.lastname='Rodriguez'} Alternatively, if you need to work on just one node and have the map you can use the each method of a map: m =

Is it possible to use Neo4j database in an Android application?

由 安稳与你 提交于 2019-12-23 10:26:56
问题 Will it make any error if I use Neo4j database for my Android Application? If so, can anyone suggest me any other Graph database to use as back end for Android application.. 回答1: Yes. While Neo4J offers a REST API to query the database with the Cypher language, I would recommend to build your own layer on top of that to deal with the requests from Android and then filter and forward to Neo4J. This layer will let you to use your own business logic between the Android app and the server, logic

Neo4j indexing (with Lucene) - good way to organize node “types”?

由 此生再无相见时 提交于 2019-12-23 10:08:08
问题 This is more actually more of a Lucene question, but it's in the context of a neo4j database. I have a database that's divided into 50 or so node types (so "collections" or "tables" in other types of dbs). Each has a subset of properties that need to be indexed, some share the same name, some don't. When searching, I always want to find nodes of a specific type, never across all nodes. I can see three ways of organizing this: One index per type, properties map naturally to index fields: index

Recursive query with sub-graph aggregation (arbitrary depth)

由 老子叫甜甜 提交于 2019-12-23 09:25:19
问题 I asked a question earlier about aggregating quantities along a graph. The two answers provided worked well, but now I am trying to extend the Cypher query it to a graph of variable depth. To summarize we start of with a bunch of leaf stores which all are associated with a particular supplier, which is a property on the Store node. Inventory is then moved along to other stores and the proportion from each supplier corresponds to their contribution to the original store. So for node B02 , S2

What does “WARNING: not changing user” mean in Neo4j?

由 自作多情 提交于 2019-12-23 07:45:43
问题 When I try to start my Neo4j database on Ubuntu 14.04, I see a message: WARNING: not changing user . What does this mean, is it important and how do I overcome the warning? The warning doesn't stop the server from starting. Full output: adam@ubuntu:~$ sudo service neo4j-service start Using additional JVM arguments: -server -XX:+DisableExplicitGC - Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dlog4j.configuration=file:conf

What does “WARNING: not changing user” mean in Neo4j?

由 ↘锁芯ラ 提交于 2019-12-23 07:44:14
问题 When I try to start my Neo4j database on Ubuntu 14.04, I see a message: WARNING: not changing user . What does this mean, is it important and how do I overcome the warning? The warning doesn't stop the server from starting. Full output: adam@ubuntu:~$ sudo service neo4j-service start Using additional JVM arguments: -server -XX:+DisableExplicitGC - Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dlog4j.configuration=file:conf

Neo4j OGM how to delete relationship

由 南笙酒味 提交于 2019-12-23 05:41:15
问题 I have two neo4j-OGM node entities connected with property-less relationship like so: @NodeEntity public class User { @Relationship(type = RelationshipNames.USER_DEVICES, direction = Relationship.UNDIRECTED) private Set<Device> devices; } @NodeEntity public class Device { @Relationship(type = RelationshipNames.USER_DEVICES, direction = Relationship.UNDIRECTED) private User user; } When I add a device to a user and then perform save, i get this graph: Later on, when i both remove the device

Neo4j OGM how to delete relationship

由 本秂侑毒 提交于 2019-12-23 05:41:15
问题 I have two neo4j-OGM node entities connected with property-less relationship like so: @NodeEntity public class User { @Relationship(type = RelationshipNames.USER_DEVICES, direction = Relationship.UNDIRECTED) private Set<Device> devices; } @NodeEntity public class Device { @Relationship(type = RelationshipNames.USER_DEVICES, direction = Relationship.UNDIRECTED) private User user; } When I add a device to a user and then perform save, i get this graph: Later on, when i both remove the device
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