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Neo4J – Linux – Configurations

After installing the community edition of Neo4J on Debian VM  understood from manuals about the need to increase the number of files limit for Neo4J. cat /proc/sys/fs/file-max The output was 3273723 – So no issues.  In case if it is less you can update it (Set it to lower value if needed, I decided not to […]

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Multiple Tomcat instances

Had to start two instances of Tomcat on the same VM (Linux) – Did the following without even knowing whether the steps were correct or not – will check later – but it worked. Unzipped the tomcat zip file into two folders In the second folder made the following changes to server.xml in conf/ folder […]

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Oracle Java 8 – Debian

Wanted to install Oracle Java on a new Wheezy system – On searching the net got the following information which worked for me apt-get install software-properties-common python-software-properties add-apt-repository ppa:webupd8team/java Edit /etc/apt/sources.list.d/webupd8team-java-wheezy.list and replace “wheezy” with “trusty” apt-get install oracle-java8-installer and that’s all!

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Neo4J – Indexes, Constraints

Cypher allows the creation of indexes over a property for all nodes that have a given label.   Neo4j CQL has provided “CREATE INDEX” command to create indexes on NODE’s or Relationship’s properties. CREATE INDEX ON :Person(name) CREATE INDEX ON :Customer (name) Neo4j CQL has provided “DROP INDEX” command to drop an existing index of a […]

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Neo4J – Delete and Remove

Main Difference between Neo4j CQL DELETE and REMOVE commands – DELETE operation is used to delete Nodes and associated Relationships. REMOVE operation is used to remove labels and properties. Similarity between Neo4j CQL DELETE and REMOVE commands – Both commands should not be used as alone. Both commands should be used with MATCH Command. Samples […]

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Ne04J – Labels / WHERE

A label is a named graph construct that is used to group nodes into sets; all nodes labeled with the same label belongs to the same set. Many database queries can work with these sets instead of the whole graph, making queries easier to write and more efficient to execute. A node may be labeled […]

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Neo4J – Relationships

In Neo4j, Relationships between two nodes are directional. They are either Uni-Directional or Bi-Directional. As Neo4j follows Property Graph Data Model, it should support only directional relationships. CREATE (<node1-details>)-[<relationship-details>]->(<node2-details>) If we observe the above syntax, it is using an arrow mark: ( ) – [ ] → ( ) . It denotes a direction from left […]

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Neo4J – A Quick Look

Features / Advantages SQL Like easy query language Neo4j CQL It follows Property Graph Data Model A graph records data in nodes and relationships. Both can have properties. This is sometimes referred to as the “Property Graph Model”. It supports Indexes by using Apache Lucence It supports UNIQUE constraints It contains a UI to execute […]

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