Http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis from
Cassandra vs MongoDB vs couchdb vs redis vs Riak vs hbase vs membase vs neo4j
While SQL databases are insanely useful tools, their monopoly ~ 15 years is coming to an end. And it was just time: I can't even count the things that were forced into relational databases, but never really fitted them.
But the differences between nosql databases are much bigger than it ever was between onesql
Neo4jIt was said thatEmbeddedInPythonInGraph databaseModule, allowing Python to operate local files through graph database APIs to store graph structure data (similar to many libraries that support SQLite ). Today, Neo4j finally fulfilled its promise on the official blog and expressed its sorry for its repeated pass jumps.
First of all, we're really sorry. we have been saying that Python support for the embedded database is coming in "a few weeks" o
Introduction: Krist óf kolács is a software architect and consultant who recently published an article comparing various nosql databases. Article by agile translation-Tang YuhuaCompile. For more information, see post-Article declaration.
Although SQL database is a very useful tool, after 15 years of outstanding performance, the monopoly will be broken. This is only a matter of time: I was forced to use relational databases, but I finally found that I could not meet my needs.
However, the differe
What is neo4j? 1. A high-performance graph relational model database 2. A nosql database 3. multiple types of support
Programming Language 4. How can I delete nodes related to a node in neo4j, which is good at processing model data with multiple relationships? 1. Find all links of the target node 2. Start a transaction, delete the Start Node or end node3. traverse all the nodes found and delete the relevan
There are two ways to use NEO4J: The embedding mode embedded and the server mode standalone, the bridge between the two is the neo4j-community-1.8.m03-windows\neo4j-community-1.8.m03\ The graph.db in data, which is replaced by the generated database folder in embedded mode, can be accessed from a generated database by 127.0.0.1:7474/webadmin in server mode.
Cypher provides a convenient way to express queries and other neo4j behaviors, cypher can not only complete the work, but also in the product has a fast enough speed. You can also work with query cases based on the Java language and use the Java API to customize the traversal method.The steps for querying the Cypher language are: parsing and validating queries, generating execution scenarios, locating the initial nodes, selecting and traversing relati
Node_1 = Graph_db.merge_one ("Test_node", "name", "hah")
node_2 = Graph_db.merge_one ("test_node_2", "name", "Enen")
rel = relationship (Node_1, "Has_test_rel", node_2)
graph_db.create (rel)
If the above code executes multiple times, there will be multiple relationships between node_1 and node_2.
How to delete an extra relationship, leaving only one bar.
Solution:
MATCH (a)-[r:has_test_rel]-> (b) with
A, B, TAIL (COLLECT (R)) as RR
WHERE size (RR) >0
FOREACH (r in RR | DELETE R)
shown in the following:4. Delete a specified relationship of two nodes1 syntax: MATCH (Node1:label1{property1:value1})-[relationship-name:relationship-label-name]-> (node2:label2{ property2:value2}) Delete R2 such as: Because Songqing book betrayed Wudang, Song and he severed the father-son relationship 3 MATCH (p1: Wudang {name: ' Song Far Bridge '})- [R: Father and Son]-> (p2: Wudang {name: ' songqing book '}) Delete RAfter the deletion of the Atlas as shown below, the two people no longer ha
;(movie),
(Other) -[:acted_in]->(movie),
(Robin:person {name:"Robin Williams" })
WHERE not (Robin)-[:acted_in]->(movie)
RETURN DISTINCT Other; 5 Index CREATE INDEX: CREATE INDEX On:movie (title);
CREATE INDEX on:P erson (name); In this case, a statement based on name or title in the query will be quick. (The purpose of the index is to speed up the query) For example, the following sentence speed will be increased: MATCH (Gene:person)-[:acted_in]->(M),
(Other)-[:acted_in]->(m)
WHE
Recently, on the basis of NEO4J Java API and RMI, a set of neo4j management tools is designed, which is divided into server side and client side, and communicates with RMI in middle. Basic functions include diagram database basic information Maintenance Management (creation, editing, deletion, statistics, etc.), graph database Data Maintenance management (create nodes and relationships, edit node and relati
neo4j download Download neo4j. Then access via http://localhost:7474
1, create the entity file CSV, you need to include a unique ID (in the way of UUID1)
2, create a relationship CSV, through the entity ID connected;
Import:
Entity 1:
LOAD CSV with HEADERS from "File:///new_entity1.csv" Asline
MERGE (Comp:company{name
Cypher Query Language simple to use3.1. Basic SyntaxNode syntax: The cypher uses a pair of parentheses to represent one of the nodes: Several formats are provided: () the anonymous node (matrix) adds an ID (: Movie) movie label label to the node, declaring the node type. The index of NOE4J uses label, each index consists of a label and a property (Matrix:movie) (Matrix:movie {title: "The Matrix"}) node attribute (for example: title) represents a Key\value list ( Matrix:movie {title: "The Matrix"
according to certain rules, usually only a subset of the sub-graphs can be accessed. The NEO4J database provides a declarative cypher language to query the graph, and neo4j generates a traversal scheme to query the graph. You can also specify the traversal scheme directly, specifying depth first or breadth first.Indexes in NEO4J can be used to speed up queries,
should be excavated further to increase the knowledge coverage of Knowledge Atlas. Common Mining Techniques:
Inference: Mining for entity attributes or relationships through a rule engine for discovering unknown implied relationships
Entity importance ordering: When querying multiple keywords, search engines will select entities that are more relevant to the query to display. Common PageRank algorithms compute the importance of entities in the knowledge map.
Second,
Tags: Technical system modification nbsp Usage src Basic Date returnAny database based on additions and deletions to the four functions, and neo4j use of the cypher language. Cypher is a very good language for working with graph databases, and here are some basic features to learn about his basic usage. Let's do a demonstration with our intelligent Motion Picture quiz System.Create a NodeThere are two ways to create a node, one is create, and the othe
Representative of the graph database: neo4j official website: http://neo4j.com/Introduction: Why use a graph databaseIn many new projects, the application of graph database is an imperative trend, because the graph database can be a good representation of the concept of various nodes and relationships, and can be very friendly visualization, greatly facilitates our data management and display work.The following is an introduction to the graphic relati
Label:NEO4J connection Java currently has embedded, JDBC, and rest APIs.JDBC: The Lib package to use: Neo4j-jdbc-2.0.1-snapshot-jar-with-dependencies.jarConnection con =DriverManager. getconnection ("jdbc:neo4j://localhost:7474/");//Create a connectionString Query= "Start N = node ({1}) return N.name"; PreparedStatement stmt=NULL;//with precompilation, unlike relational databases, parameters need to use {1},{2} instead of?ResultSet rs =NULL; Try{stmt=
First, the preface
This article is "The Knowledge Atlas actual combat development Case Complete Analysis" series article and NetEase Cloud Video Course's external article, mainly records the student in the Knowledge Atlas and so on related content study
In the process, the common problems raised are discussed. This part of the content of the original content recorded in the NetEase cloud classroom "knowledge map actual combat development Case complete analysis" discussion area.
Interested stu
side is not present, increase the relationship: MATCH (Clint:person), (Mystic:movie)
WHERE clint.name="Clint Eastwood" and mystic.title="mystic River "
MERGE (Clint)-[:D irected]->(mystic)
RETURN Clint, mystic; A more complicated example: Increased understanding knows relationship: A film actor and actor, actor or director, or director and Director may know: MATCH (a)-[:acted_in|:D Irected]-> () (b)
WHERE not (a)-[:knows]-(b)
MERGE (a)-[:knows]-> (b); 5 deleting nodes and edges Match (
JDK is the core of the entire Java, including the Java Runtime Environment (Java runtime envirnment), a bunch of Java tools and the Basic Java class library (RT. Jar ). No matter what Java application server is actually built into a certain version of JDK. Therefore, mastering JDK is the first step to learn java well. The most popular JDK is the JDK released by Sun. In addition to sun, many companies and organizations have developed their own JDK, such as JDK developed by IBM and jrocket of Bea,
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