Bath Ruby 2 - Coraline Ada Ehmke: How Neo4j saved my relationship
11 Mar, 2016
1 minute read
“people should not be shits to each other online”
Relational databases are designed for backing forms
Not always the best way to store data
Graph theory - originated with Euler
Data suited to a graph db:
Where context is important - needed to understand the data
Nodes and Edges
Edges are relationships between nodes
relationships are first class citizens (unlike join tables)
Graph dbs have Much better performance: linear, constant (RDBs performance
degrade worst)
Good for agile because they don’t lock you in to a particular data
structure.
Relations + Metadata = facts - extract facts and model as nodes instead of
edges
The graph db doesn’t care what is stored in a node: things don’t have to be
in any particular structure.
Neo4j
different stores: Node, property, relation
Fixed-size records for Node and relationship data -
this enables superfast lookups because
you know where a record will exist in memory.
Query language - Cypher
AScii art to represent relationships! :D (a)-[:follows]->(b)
When deleting nodes, you have to detach from any existing relationships
pointing at that node
Neo4j console is a single-page webapp, with shiny interactive represenations
of the graph
Interaction with ruby: via a gem - build queries in mostly the same way that
you would if writing it directly in plain text. Get a struct back with the data
neo4j for AI:
Sophia - Coraline’s AI project
aim is to create metaphors
models contexts like beauty, animals etc..
models synonyms and antonyms
models facts about the terms - uses these to answer questions - e.g. “do
cats have tails?”
When to use:
when relations/metadata are as important as the data itself
