Neo4j

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Neo4j is a graph database.

It is not like Oracle or SQL Server - no tables and primary keys with associated foreign keys.

Sounds .......... scary
Sounds........... different

But when you map out a workflow on a piece of paper, drawing boxes and circles and joinging them with lines, you create a graph. It's what comes naturally.


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Property DataType - apoc.meta.type

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Node Properties in Neo4j. A property can be of any datatype even within nodes of the same label. Nodes have no fixed schema as with the RDBMS where most notions of data storage are formed and 'best practice' is enforced.  Properties themselves do not have types, but the values they hold do. However, you can have a property, X which could be assigned a string value or a numeric value. There is no enforcement of typing for a property. Of course, it would not (always) make sense to assign a property different type values in your graph. So, just what datatype is the property? Trusty APOC has a function for that. WITH [true, 42, 'foo', 1.2] AS data UNWIND data as value RETURN apoc.meta.type(value) So, just what datatype is the property? "BOOLEAN" "INTEGER" "STRING" "FLOAT" You can use this function in MATCHES on nodes in your system where properties are unknown at runtime. MATCH (n:MyNode) RETURN apoc.meta.type(n.MyProperty)
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Stopping and Starting the Neo4j Database

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Controlling the service System services are controlled with the systemctl command. It accepts a number of commands and follows the format: systemctl {start|stop|restart} neo4j you may find that you need to prefix the systemctl command with sudo like: sudo systemctl stop neo4j looking at the output of the status command we get :   sudo systemctl status neo4j ● neo4j.service - Neo4j Graph Database    Loaded: loaded (/etc/systemd/system/neo4j.service; enabled; vendor preset: enabled)    Active: active (running) since Thu 2020-07-23 09:53:29 UTC; 1h 33min ago  Main PID: 958 (pre-neo4j.sh)     Tasks: 64    Memory: 14.3G       CPU: 22min 1.740s    CGroup: /system.slice/neo4j.service            ├─ 958 /bin/bash /etc/neo4j/pre-neo4j.sh            ├─ 996 /bin/sh /etc/neo4j/reset-password-aws.sh            ├─ 997 /usr/bin/java -cp /va...
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